Yianaros the Spirit

Lonamin can use her Tooth Fairy powers to make spirits reveal their true form. Therefore she can probably make Yianaros temporarily unable to hide herself as a rock. However, if this power is used, the Musical Spirits around will become disturbed and will start attacking. Therefore, you need to be careful.

※ There is no penalty from being killed by Musical Spirits. However, Mounts must be placed in a safe spot.
※ Musical Spirits cannot see very well, so if you move in a crouched position, they will not attack you.