Does Morvran only offer his slayer challenge once? I read that he does on Rune Wiki, but I cannot find any verifying information anywhere else.

 

To be fair, the wiki could be saying that each boss has to be killed "once" but it is misleading.

Unlimited (although i have no idea why you'd every want to do it again).

Yeah it can be offered infinitely same as all other masters special challenges.

 

I think the emphasis on once is due to the fact the wording of the task itself can be misleading as it just refers to killing 9 bosses from a specific list, which is rather ambiguous on the fact its killing each one of the 9 once - not just killing 9 in all.

Oh, no. I have not done it yet, but I read it as if you only have one opportunity to complete it.

 

Edit: Exactly, Sy.

RuneScape Wiki says "Morvran will ask the player to slay a group of bosses once" (emphasis mine) and I think they are referring to you having to get one kill on each boss, not that Morvan will only assign the special challenge one time. Given that it's required for the Completionist Cape, I have a feeling someone would have complained and gotten it fixed if there was only one opportunity to get the challenge ever. So yeah, you can cancel it without penalty and you should get it again some point in the future.

 

Edit: looks like it already got answered while I was typing, cheers :).

Wiki changed.

It is fairly common to get the challenge from him. You do not get the challenge once, you can get it multiple times. The challenge itself is "kill each of the bosses once while you have your inventory with crystals"