In the past there have have been excellent Reaver guides available in the Net, but regrettably most of them have been lost in the tumults of time. Here's my take on the matter, feel free to fill in the facts.

This is a rough outline of Reavers, a very atmospheric and effective Evil Religious background (off-)tanking guild.

What are the Reavers?
Reavers are the de facto tanking guild in ERelig background. They have quite a few means of dealing burst damage via spells, and they have one of the most powerful offensive skills in the game. Including few unique skills that allow them to deal elemental damage with skills. Reaver levels pair up quite decently with any setup, lending tanking abilities to spellcasting and spellcasting elements to more martial guilds. Full reavers are also entitled to take levels of Navigator guild.

Reputation system.
Reavers have a reputation system that is an integral part of gaining power in the guild. Reavers release energy by killing things, and in a smaller extent by destroying non-living things. Only restriction is that damaging the killed creature must INCLUDE use of reaver-specific skills or spells. Finishing off the mob release the energy, and scoring the killing blow yields some extra. You need not necessarily kill the mob, but you must be online when the killing is done.
There are four layers of reputation in the guild. When entering the guild first time, you will be on Layer1. By limited testing, 1meg of experience equals to 1/4 toward second layer energy, 6% toward third layer and more than 1% toward fourth and final layer. These figures may vary, since experience is not a fixed value and foremost NOT a deciding factor upon which the amount of released energy is based. In any case, reaching the final layer is relatively easy compared to few other reputation systems in the game. Reaver energy detoriorates when not collected, speed of which is debatable. If you idle for 4 months, you WILL have dropped from layer 3 to 1. Reincing out of reavers does not drain your reputation, but staying out of reaver guild will eventually cause detorioration.
Secondary reputation system for the guild is Spitemarks[\b]. Spitemarks are collected solely by casting the weakest offensive reaverspell, Word of Spite. These marks affect Reaverspells Word of Slaughter and Word of Apocalypse. It is also said that amount of marks will power up Word of Spite itself, but I have not been able to confirm this rumour. Amount of spitemarks by race can be checked by casting Detect race at an opponent, which reveals amount of marks against mobs of its type. Whole list of spitemarks is accessible by using syntax; Prayer of destruction at spell spite. You might have to use it a few times, its proc rate seems quite random.
[b]
Spite marks.
Spite marks are a way of collecting a secondary reputation for Reaver guild. In empiric tsting, spitemarks have been noted to have an effect on few reaver spells. Spitemarks are not necessarily needed, and the lack of them does not break your game.

Guild quests.
Reavers have a multitude of guild quests. Some quests have significant rewards when finished, but all of the relevant series must be completed. Some are [Rush] quests, that need to be finished in certain timeframe, most reset upon reinc but very few last through it. Finishing all reaver quests require time and dedication. Additionally, there's rumored to be a few hidden quests.

Tactics. Spells. Skills.
Being full guild Reaver does not entitle you to train all skills and spells in the guild. Gaining energy allows you to enter hgher layers, that have sets of trainable skills and spells.
Layer1: Does Not Work Single guild. You get 2 weapon skills and the weakest offensive splls and skills in the guild.
Layer2: You get few essential skills and spells, but still it does not compare to most "effective" guilds. Word of Blasting makes spellcaster reavers effective.
Layer3: Here the power begins. Comparable to most other guilds in power. Mastery skill is acquired here, which makes Call Armour, Call Weapon and Shattered Feast quite powerful spells.
Layer4: Just topping on the cake.

Word of Spite, Slaughter, and Genocide. Apocalypse.
These spells go hand in hand. Their damage is dependant on the amount of spitemarks, or the amount on spitemarks on the targeted monsters race. Genocide is a race-targetted areaspell with similar damageoutput as Slaughter. Apocalypse damages all mobs in the room according to their spitedata. Nasty one to be casted while partying.

Word of attrition, Blasting, Destruction and Oblivion. Black hole.
While linked together, these spells are each quite different in effect. Attrition destroys items on ground, Blasting is strict direct damage spell, while Destruction attempt to destroy a single equipment worn by monster + damages them. Black hole does immense damage + empties the room. If mob dies, its corpse is also destroyed. Word of Oblivion is Destruction on steroids, attempting to blast every single item worn by target. Damage against items worn by players is sadly/radically reduced.
On energy detorioration and spell use
Most reaver-specific spells (words of whatever, calling spells, shattered feast) use a small amount of energy. In most cases this is a negligible amount, which apparently is a way to prevent collecting energy while in Reaver Freeze-condition. Reaver freeze prevents energy detorioration while in a reaver reinc, but when you are not actively collecting energy. Normally, few days of idling is allowed, but somewhere between four days to one full week the detorioration starts ticking your precious reputation away. Again, the detorioration is greater on higher layers.
Several spells can be toggled as to how great an impact on energy you wish them to have. For example, Shattered Feast can be cast "on amount" between 1 and 100. Feast at value 1 heals equally or less to Cure Light Wounds, while at value 100 you can reach quite effective heals (at 190wis, a 360hp heal for 65-ish sp is not that bad). On highest consumption, it takes away a "Tiny" amount of reaver energy, which can be mitigated by shooting a rabbit or any outerworld bird with a Word of Spite. There is never a single reason NOT to cast this at amount 100. This is a good base line for any reaver spell: If there is an option to cast it at full power, Do It. Manaefficiency is horrible otherwise, and the energy loss is quickly recovered. Only spells that have an impact on energy accumulation, and even them are only meaningful for beginners (commonly referred to as "newbies"), are spells Call Armour and Black Hole. Call Armour hogs a "Vast" amount of energy, which can be mitigated by partying for less than half an hour in an exp party and spamming Word of Blasting. Black Hole is countereffective to energy gathering since it as itself is a spammable spell, and an effective damage dealer. However, if you are able to cast Black Hole, your greatest interest hardly is gathering more energy. You filthy highbie.

Reincing to reavers.
A very good advice is to not attempt to reinc full into reavers, unless you have been a partial reaver before. 7 levels of reavers is generally considered enough to collect reaver energy for second or even third layer. Some combinations are more forgiving than others, but there's not much gained from reaver guild until third layer.

Which race
I'm of the opinion that any big race does well as a reaver. All of the reaver spells are tied to Wisdom though, and in my experience a certain minimum must be reached for reaver spells to be effective. 150 is a bare minimum, but difference between 150 and 190 is astounding. Join a secret society today, you won't regret it.
Races for multiple guild combinations is a whole different matter. In my experience, a Cyclops Reaver is playable with sizzling locblade and reaver strike skills, although it might be quite far from anything most people would call "optimal". Likewise, a priest with reaver for added defense will probable look for a caster race, rather than high con/size/str.

Equipment.
Reavers get mediocre(90) skill on axes and polearms, Combat sense to 80 and eventually a decent dodge/parry(75). These should guide you in acquiring the gear for reaver.
Reavers also get a fancy scythe from a spell (eats up small amount of your reputation each time you summon it) and a very good armour(o-yoroi slots, vlw if summoned with 90+ mastery). Before layer 3 these are more of a curiosity, not nearly as good as final versions. Yes, you get hshreds with the gleaming black scythe. Yes, the vortex armour gives some UNGODLY prots to a tank race. Tools of the Trade.

My 2mowgles.

Excellent shite.

One request though. Add something on the use of shattered feast, mainly its efficiency and energy usage.

Here are the skill and spell tables for the guild:

GUILD: reaver

+-------------------+------------------------------------------------------------------------------------------+
|SKILLS . / . LEVEL | 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30|
+-------------------+------------------------------------------------------------------------------------------+
|Attack ............| 20 25 30 35 40 45 50 55 60 65 70 85 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Axes ..............| 10 20 30 40 50 60 70 80 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90|
|Polearms ..........| 10 20 30 40 50 60 70 80 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90|
|Consider ..........| 05 10 15 20 25 30 35 40 45 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50|
|Appraise ..........| 05 10 15 20 25 30 35 40 45 50 55 60 65 65 65 65 65 65 65 65 65 65 65 65 65 65 65 65 65 65|
|Cast generic ......| 10 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Cast destruction ..| 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Reave shield ......| 10 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Mana control ......| 05 10 15 20 25 30 35 40 45 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50|
|Scythe swipe ......| 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Prayer ............| 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Discipline ........| -- -- 05 05 10 10 15 15 20 20 25 25 30 30 35 35 40 40 45 45 50 50 50 50 50 50 50 50 50 50|
|Reave weapon ......| -- -- -- 10 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Bash ..............| -- -- -- -- 10 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Parry .............| -- -- -- -- -- 03 06 09 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75|
|Dodge .............| -- -- -- -- -- 05 05 10 10 15 15 20 20 25 25 30 30 35 35 40 40 45 45 50 55 60 65 70 75 75|
|Throw weight ......| -- -- -- -- -- 05 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 00 00 00 00 00 00|
|Reave armour ......| -- -- -- -- -- -- 10 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Rampant cutting ...| -- -- -- -- -- -- -- 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Riot ..............| -- -- -- -- -- -- -- -- -- 10 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00|
|Combat sense ......| -- -- -- -- -- -- -- -- -- 05 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 80 80 80 80 80|
|Endurance .........| -- -- -- -- -- -- -- -- -- 10 10 10 10 10 10 10 10 10 10 20 20 20 20 20 20 20 20 20 20 35|
|True reaving ......| -- -- -- -- -- -- -- -- -- -- 05 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 00|
|Way of the scythe .| -- -- -- -- -- -- -- -- -- -- 05 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 00|
|Infernal arc ......| -- -- -- -- -- -- -- -- -- -- -- 10 20 20 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00|
|Corrosive cut .....| -- -- -- -- -- -- -- -- -- -- -- 10 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00|
|Cleave ............| -- -- -- -- -- -- -- -- -- -- -- 05 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 80 80 80|
|Impale ............| -- -- -- -- -- -- -- -- -- -- -- 05 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 80 80 80|
|Combat damage analy| -- -- -- -- -- -- -- -- -- -- -- -- 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 95 95|
|Stun ..............| -- -- -- -- -- -- -- -- -- -- -- -- -- 10 15 20 25 30 35 40 45 50 55 60 65 70 70 70 70 70|
|Reaver strike .....| -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00|
|Enhance criticals .| -- -- -- -- -- -- -- -- -- -- -- -- -- -- 05 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80|
|Mastery of destruct| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 05 10 15 20 25 30 35 40 45 50 55 60 65 70 00|
|Stunned maneuvers .| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 05 10 15 20 25 30 35 40 45 50 55 60 60 60|
|Tumbling attack ...| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 05 10 15 20 25 30 30 30 30 30 30 30 30 30|
|Wrath of hells wind| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 10 20 30 40 50 60 70 80 90 00 00 00 00|
|Breath of doom ....| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 10 20 30 40 50 60 70 80 90 00 00 00 00|
|Rebellion .........| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 10 20 30 40 50 60 70 80 90 00 00|
|Riposte ...........| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 05 10 15 20 25 30 35 40 45 50 50|
|Find weakness .....| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 05 10 15 20 25 30 35 40 45 50 50|
|Reaving ...........| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20 30 40 50 60 70 80 80 80 80|
|Mangle ............| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20 30 40 50 60 70 80 80 80 80|
|Blood harvest .....| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20 30 40 50 60 70 80 90 00|
+-------------------+------------------------------------------------------------------------------------------+


+-------------------+------------------------------------------------------------------------------------------+
|SPELLS . / . LEVEL | 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30|
+-------------------+------------------------------------------------------------------------------------------+
|Word of attrition .| 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Darkness ..........| 10 20 30 40 50 60 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70|
|Call scythe .......| -- 10 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Destroy water .....| -- 10 20 30 40 50 60 70 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Word of spite .....| -- -- 10 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Detect race .......| -- -- 20 40 60 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Call armour .......| -- -- -- -- 10 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Infravision .......| -- -- -- -- 20 30 40 50 60 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70|
|Immolate scythe ...| -- -- -- -- -- 10 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Reaping of bile ...| -- -- -- -- -- 10 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00|
|Shattered feast ...| -- -- -- -- -- -- -- -- -- -- 10 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00|
|Word of blasting ..| -- -- -- -- -- -- -- -- -- -- -- -- 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00|
|Word of slaughter .| -- -- -- -- -- -- -- -- -- -- -- -- 30 40 50 60 70 80 90 00 00 00 00 00 00 00 00 00 00 00|
|Glory of destructio| -- -- -- -- -- -- -- -- -- -- -- -- -- -- 10 20 30 40 50 60 70 80 90 00 00 00 00 00 00 00|
|Word of destruction| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30 40 50 60 70 80 90 00 00 00 00 00 00|
|Word of genocide ..| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30 40 50 60 80 80 90 00 00 00 00 00 00|
|Blood seeker ......| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 10 20 30 40 50 60 70 80 90 00 00 00 00|
|Spirit drain ......| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 10 20 30 40 50 60 70 80 90 00 00|
|Word of oblivion ..| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30 40 50 60 70 80 90 00|
|Word of apocalypse | -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30 40 50 60 70 80 90 00|
|Black hole ........| -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 05 15 30 50 00|
+-------------------+------------------------------------------------------------------------------------------+

I know it requires some manual labor, but getting also a list of skills/spells on different layers would rock.

Instead, I could put a link to pages where Blackstarr has listed those skills by Layer;
http://www.angelfire.com/rpg2/switchboard/revsort.txt

This is the super useful call armour information from the news groups.





Cheers,
Askan

Just a note on the skills/spells.

Elemental Skills (infernal arc, corrosive cut)

These skills work with weapons that do fire and acid damage respectively. The weapon has to be your primary one (wielded in right hand, no idea for barsos).

You cast the equivalent spells to get the skills to work on your weapons. What's even better for those who don't like to micromanage (myself included) is that the skills work if the weapon is naturally fire/acid damage type.

ie. The thana voulge is flaming. Meet a pr monster, wield the voulge in your right hand and arc away. Toasty!

Glory of Destruction

Wisdom affects the stat increase (+str/dex/con), mastery affects the duration.
With around 100 mastery the spell was lasting ~12 minutes.
This was with a spell % of ~85%

Askan

Selection of armour is of course your personal preference. Gleaming plate seems to give the best prots of the three, while Whirling vortex is vlw. The gleaming plate also hogs essentially every slot you have, barring use of any StatEQ you might want to wear. Or spr-set, since reaver armour cannot be removed once worn. Also depending on your guild selection and other eq, your dodge/parry may provide a greater survivability with vortex armour than maxing your prots with heavy plate.

Your mileage may vary.