So first, everyone thinks Io sucks. They are wrong.

Skills guide

lvl 1:stats

lvl 2vercharge

lvl 3:stats

lvl 4:spirits

lvl 5:stats

lvl 6:relocate

lvl 7vercharge

lvl 8:stats

lvl 9:tether

lvl 10:tether

lvl 11:relocate

lvl 12vercharge

lvl 13:spirits

lvl 14:stats

lvl 15:tether

lvl 16:relocate

lvl 17vercharge

lvl 18:spirits

lvl 19:stats

lvl 20:spirits

lvl 21:stats

lvl 22:stats

lvl 23:stats

lvl 24:stats

lvl 25:stats

Items

First off, get a few healing items, like bottle.
Then, go for heart of torrasque (idk spelling)
and sacred relic.
Keep healing items handy, this guy is weak early on