Soulcalibur is becoming a mobile game. Bandai Namco has announced Unbreakable Soul--and that's about it. You can see this logo (above), but no other details have been revealed other than the fact that it's "coming soon."
The last time Bandai Namco adapted a fighting franchise onto mobile, they created Tekken Card Tournament, a drastic departure from the mainline series. And while platforms haven't been announced for Soulcalibur: Unbreakable Soul, Tekken Card Tournament appeared on both iOS and Android.