There are plenthora of gems that cant be cast manually, but instead have a chance to occur on/when hit. Utilizing those gems with autocast traits currently is a thing. While most of them seem ok, though it rather defeat the purpose, mutilate is definitely an overkill, set targets health to 1, combine it with cast on extra target and it will wipe quite a few of your/enemy creatures (well not wipe, but victory will depend on turn order, if any other spells are in autocast sequence, in any case leaving creatures unable to cast health-based, and prone to culling via any damage/judgement) have it on all your creatures and well. And if you ll run into multiple pallida that stacks and has that gems, good chance that prior to combat it will be your team/most of it with 1hp. Its still ok if you are running speed based team of any sort, otherwise its a bit weird mechanics.
Please note that mutilate works regardless of stats, its easly and instakill if combined with any followup and cannot be resisted, imo even having cast on extra target in it is OP, but having it castable through auto-trait before the battle is a lil nuts.