Well this is certainly unexpected: the latest third-party game to be represented in Super Smash Bros. Ultimate is Warframe, as two characters from the space ninja game are joining Smash as spirits.
As part of Nintendo's Spirits in Black five-day event starting this Friday (not the Slayer song), players will be able to unlock both Lotus and her recently-transformed version Natah. To claim her, you'll need to beat Bayonetta in the Spirit Board. She's a two-star advanced, neutral, primary unit with three open slots, and as an enhanceable spirit will transform at level 99 (thanks, Siliconera). Here's a little preview of what she'll look like:
In keeping with the event's theme, players will also be able to catch up on a variety of other shady spirits they may have missed: including Darkrai, Bullet Bill, Infinite, Judge, Zekrom, Oil Panic, Raphael the Raven, Fire and Turtle Bridge.