I have a couple questions about Mahkleb's powers.
1) Once you get the upgraded unleash destruction and the infernal mark, am I correct in thinking that you keep these no matter how low your piety drops? And related to that, am I correct that the power of your summons is entirely dependent on your Invocations skill, not on your piety level? I'm at 6 pips of piety, so I'm thinking I could/should be using Infernal Servant more often. I guess the downside of that would be lowering the Gain Health from Killing.
2) A bit of a rhetorical question, but ... am I missing something about Unleash Destruction? It doesn't seem all that powerful. I suppose it matters that I'm playing as a Djinni, so that it currently costs me 13 HP for 3d18, which seems really expensive for not that much damage. It's doing some work for me now, given that even at level 22, I don't have a full-range, single-target spell of this nature. But, more seriously, what do people think about it, and in what situations would you find it useful?