My favourite is to distract him with bees.
Wild that blindness doesn't work when affection does.
Tengus interaction with charm is weird. He stops throwing shurikens at you, but will still use other abilities as normal (cause they aren't direct attacks, I guess?). This makes affection very helpful for the first phase and not as helpful for the second.
Same as, when you are charmed, can't directly attack enemies but can use wands and other items to attack them. A discrepancy I detect though is that, while you can throw throwables while charmed at the enemy you are charmed, Tengu can't.