First, I would like to say that Bat City monsters appear to repop now (well,
most of them, maybe not the special ones like Athalon). This alone should
resolve any "ownership" problems.

Secondly, it is a part of BatMUD that sometimes quest monsters, for whatever
reason, die. Some are strong, like the registration guy. Others not so much.
It makes a quest harder when the required monsters are weak enough to be
killed. Many players here kill quest monsters from time to time. Some are good
exp, others carry clearly valable items, and others just wander arond in clear
view. I can't think of a quest monster offhand which is once-a-boot AND weak
AND carrying valuable items, but there may be one. Such a monster would make a
quest very hard.

I will say that it is generally considered in bad taste to "farm" monsters
that are part of a quest (guild, area, level, etc). A kill of opportunity is
one thing, but deliberately waiting for them to repop so you can wipe it again
will eventually make you unpopular.

Shinarae Lluminus