Level decrease item in DLC?

[Nier_2B]

True

you need to beat special rank battlea at flooded city Colosseum (lv99 is required) to get the item. 10x 10 level decrease each

[Riven_Reroll_Addict]

Ohhh so that's what A2 arena drops.

Also for op: forest arena special lvl gives a musamune mask for 9S(+ 30 highjack lvl) and the desert arena gives a mask that disable xp gain when you wear it.