Yokai Event

[Theodric]

It was also completely optional.

Technically, yes - but for people who enjoy collecting mounts and minions to the point where that consumes a lot of their time and focus in-game? Not so much. I did it because I like collecting stuff - but it was very tedious and dull. The challenge could have come from something more engaging especially when the game already relies heavily on FATE's to artificially make certain items harder to acquire.