Lydia Frye can't be blocked by creatures with power 3 or greater.
At the beginning of your end step, surveil X, where X is the number of tapped Assassins you control. (Look at the top X cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
Lydia Frye leads an Assassin tribal deck that combines evasive attackers with graveyard value. Deploy a wide board of Assassins, tap them out attacking each turn, then surveil heavily on your end step to fuel reanimation, delve, and card selection. You grind incremental advantage while Lydia herself slips through for unblockable damage and even fits into the broader Assassin's Creed flavor shell.
Cheap, hard-to-block commander that pressures early and triggers reliably
Free repeatable surveil engine that buries no-cost graveyard payoffs and fixes draws
Scales with a wide tapped Assassin board, rewarding go-wide tribal builds
UB gives access to premium removal, tutors, and recursion
Surveil requires Assassins to be tapped, so a wiped board shuts off the engine
Tribal payoffs in Assassins are thinner than Goblins or Elves
Lydia provides no inherent protection and dies to spot removal easily
Damage output from a 3-power-or-less evasion clock is slow against big life totals
Turns milled Assassins and other creatures into a recurring army and scry/drain engine.
Add cheap interaction (Fatal Push, Swords to Plowshares isn't legal here—use Cut Down, Go for the Throat) and protection like Heroic Intervention's black equivalents to keep your board intact. Lean into delve and reanimation payoffs (Murderous Cut, Animate Dead, Reanimate) so the surveil actually converts to advantage, and include tutors like Demonic Tutor and Vampiric Tutor to assemble your engine. Mana rocks and dual lands smooth the UB base and let you double-spell to rebuild after wraths.