It's called Iron Will.
Are there any yellow buttons?
H-huh?
They're only hitting Momoi!!
Why is that?...
Stance......? *panic*...
Which one is it!?
.........!!There it is!!
Aris-chan!
You forgot your Stance!
Stop...
Get away!!
*panic*A rough explanation that you don't need to read.
※ Stance: The role of a Paladin is to use their high defensive power to draw enemy attacks to protect everyone in the party! (=Tank)
To do this, there are skills to attract monsters' attention; the general term for this is Stance. Without utilizing Stance, the attacks of monsters will be concentrated on the person with the highest attack power.
However, each job has a different name for it (Paladin= Iron Will, Warrior= Defiance, etc), so beginners tend to ask "What's stance?".
※ What's that grass growing on Aris's head?: It is commonly known as the "sprout mark". It is given to those who have just started playing the game. After a set amount of playtime + a certain amount of main quest completion the mark disappears. Panicked Aris is so cute. ♥