The Wraith is a combat mount that also exists on P2P, albeit with slightly different abilities.
It was the first combat mount that was shared with P2P.
As of writing, it's considered the best mount in the whole game, thanks to it's healthpool and low cooldown flash ability.
All Combat mounts can be acquired via the Mosaic Sale.
This mount can be upgraded with a reactor from the Mosiac Sale.
More info on upgrading can be found here.