Wikia is correct indeed. She has it, on the same line as her 20% attack buff.
P.S. The forum doesn't properly render some Japanese characters, so I have to use the code tags to make them show up.Code:ボスに対して与えるダメージが15%増加する
5★ sealstones. Exchange for any 5★ introduced in 2016 and 2015 respectively.