The Double Phantom: Straight rogue damage build for D&D 5e https://www.youtube.com/watch?v=bKF5TR8U6_o
A mount doesn't use your movement... using bonus action for Steady Aim to give advantage.
Feat: Elven Accuracy
Subclass - Phantom
Phantom Steed Ritual Spell
High Elf (or Half Elf) - Booming Blade Cantrip
Point Buy: 8/15/13/10/15/10
Rapier + Heavy Crossbow Expertise in Perception, Investigation? Stealth?
Feat 4: Elven Accuracy Feat 8: Ritual Caster (WIZ): Find Familiar, Phantom Steed... Comprehend Languages, Detect Magic, Unseen Servant, Water Breathing, Telepathic Bond Feat 10: ASI +2 DEX Feat 12: Shadow Touched (Silent Image), Lucky, Mounted Combatant, or max out CON.. Tough
Ghost Walk at 13 is very, very strong (Ground Peeking? Falling into the ground, taking 1d10 damage, coming up to attack)
Tokens of the Departed is crucial (Wails of the Grave is effectively infinite).. you can technically constantly kill your Phantom Steeds (I disagree about this working.. I would say the Phantom Steed isn't a creature...)
https://www.dndbeyond.com/characters/63358141 https://docs.google.com/document/d/1gv_81HPSh6v1VAZk7ZIxfY7hzzZj1A0ckdNKc2PpCdU/edit
https://www.youtube.com/watch?v=zg0bAl1WPGQ