Wizard – “Audacious Wizard” [Campaign 6, Mission 1]

In the end, they never offered me the logistics upgrade. It could have been achieved by restarting the third mission (there's a hut there), but I was too lazy. I took the defense upgrade and became arrogant... Education.
In general, Zehir is a beast; his specialty is no worse than that of Agrail-Railag.

Yeah, it's a great ability. But you're going to resurrect fallen units, only to find that elementals appear in their place. If you killed 5 gremlins, then, of course, it's not a big deal, but if you lost a squad of titans or mages (and most likely, djinn, which the AI units don't like), then you often can't resurrect them. The elementals are "locked" by the units that killed your units, and you can't free the "corpse." And even if you do manage to free them, the elemental, instead of fighting, just crawls back and forth on the next turn... very useful, who would argue.
Resurrecting ghosts instead of fallen enemies, like Naadir does, is a really useful thing. Especially when the units that were protecting the archers are killed - the archers are blocked, the enemy rushes to attack the ghosts, and "we don't care" - it's not a pity to lose the summoned ghosts.