Raven, after landing with the cataclysmic effect of her talent ability, immediately began to use her dual blade style.
The Kageyama dual blade arts was a lineage art, one brought about by a Heritage.
That was the amazing thing about Heritages: they could be passed down. It's not even a must for the successor to be related by blood; it was something that could be passed as long as the successor is a drifter.
But most clans and families preferred to pass it down to their own blood, so one way or another, heroes past that had obtained amazing heritage had ended up creating diverse families with diverse lineage arts.
The Kageyama Clan was one of such; their first patriarch was a great assassin with a dark element talent ability. It later formed their familiarity with the darkness; their distinguished jet-black hair was also something quite known to their family.