Nahida

Lemme pull an erm actually here; The wisest is actually Morax, purely through experience since he's 6,000 years old. For Nahidas age, she's pretty wise, mostly because when she was trapped, she read and read to try and prove herself worthy of being as great as Rhukkedevata. I'd say they're pretty close though.

nahida when THOSE students try to break down trees at the Akedemiya

if you ask her about her opinion on the sumeru archon she doesn't talk about herself

I love her she reminds me so much of gentian impact!!!!