Hello.
Like stated above, that "Unknown" message will occur if Zulrah died to a cause other than you (the player). If you screenshot the message saying "Unknown has completed the Trials" and submit it in a support ticket at manacube.com/support, they will be able to reward you the win and tokens that you should have gotten. Creepers also spawn randomly which may just depend on chance or which arena you chose. I have played many trials and throughout each, creeper spawning was always very inconsistent. This shouldn't be a problem though since if you do get creepers, they are easy to kill and give tons of xp!