One Up + Hex Spells + Deviant Casting
Eren has started perfecting the use of his support-type spell One Up which would allow him to cast a Rank-2-like spell while still being in Rank-1. It just used a higher amount of mana, something he had an abundance of.
However, One Up had a problem. It would take a lot of time for him to use it in conjunction with the required spell. Even using it to cast Hex spells didn't solve that problem for him.
That's when he started using the deviant casting technique he had learned from Aleph. It allowed Eren to cast spells in their half-baked format, cutting their casting time. The spells became unstable as a result. But that played into Eren's strength as it made them more lethal. He would inject more mana into the spell's basic build block, increasing their instability and lethality along with it.
Blitz Wave
