DMM has a new item for the stamp card (Legendary and Super Legendary specifically). The platinum ticket allows you to roll for a platinum+ rarity unit. It's like a shrine summon but for platinums and blacks only.
About the April Fools event. Just beat it and got my SC. I was hoping to get those two units that were in the map lolz. Ah well, at least it gave me a chance to use Raven.
Back to the main event. I'm going to try using Charlotte and Sukuha and see if they are effective for the 50/5 map.