Talk:Yui Kusanagi (Dark Assassin)/@comment-162.194.208.67-20140522051957/@comment-24802371-20140523022546

Finishing all the 4 towers can get 4 Yui, and the lucky one can get 2 drop.

As a drop on 20th floor is not guaranteed, we have to run at least 13 more times in Spire of Thunder.

MP required = 13 x 200 = 2600 MP.

Time needed to recover MP naturally = 2600 x 5 / 60 / 24 = 9 days 40 minutes.

Sure the time needed will be shorten when level up.

I still think that hunting for ether bottle in the future is better.