When they were assigned to be Aerine's bodyguards, she recalled that they mentioned, or specifically, Mai was also instructed to train Aerine to be able to protect herself by Lucian.
Aerine was also extremely willing to do so. However, looking at Mai and the suspicious light in her eyes, Aerine was also reminded of the stunned expression of Mils after hearing Mai would be training her.
If she could recall it right... her training routine was enough to gain a huge reaction from Mils, but Mai refuted and defended her methods by saying they were not exclusive to devils.
Was her method really that excessive? For a moment, Aerine hesitated since she also knew how unreliable Mai acted sometimes. However, it was only a moment before she shook these thoughts.
This won't do. If she wanted to get stronger, she had to practice her will and not be dissuaded by how hard the training was. So, in the end, Aerine could only nod her head.