Enderflames.
Eren felt like the green flames had a mind of their own. They were so powerful in intent that they were practically able to incinerate any object they encountered.
The green flames carried Eliza's wrath. They easily overpowered Eren's fire-element spells by incinerating the orange flames themselves.
And this was when Eren was keeping things restricted to Adept rank where he was most comfortable using his spells. As a result, Eliza's attacks were also restricted to the same rank as his.
The butcher had just broken into the Expert rank. If he chose to face his opponents while using his original rank, Eliza would have a significant advantage. She would have a much more capable platform to express her individuality through the Enderflames.
