best way to get up there is using the Spike Boots or another Accesery that Boosts your Jump, since you cant use Abilities liek Teleport & Ignore Hieght.

Ninja's and Dragoons have pritty high Natural Jump so they Might be able to get up without an Accesery, But honestly your going to the volcano JUST for the sword so might as well just use the accesory anyway cuz youll feel like a tard if you cant reach and have to do the level again or reset, lol.