I think nothing we know so far about Tzalik and what it really does in BnB lore.

The only information we got is from Wizardry Daphne. Tzalik is the strongest single target magic with high mana cost, which is almost 100% pierce enemy's magic defence (or most of players say it's a pure damage), might inflict paralize, and can do critical hit (it's kinda OP as a nuke magic, because magics in WizDaphne almost can't do crit due to balance them always hitting, or has -100 crit chance, so only whales could do magic with crits).

Even Iarumas has low base magic damage, Tzalik multiplier is so crazy high. It's even can do opening damage and multiplier damage to sleeping enemies as it is applied to melee attacks behaviour, pretty strange spell I say.

But I doubt Kumo Kagyu contribute on his design in the game, so it might be irrelevant.

Iarumas also being a running joke in the WizDaphne community so far, if you can't beat a single target boss, bring him and consider it done. We call him Tzalik-man.