Pantheon + Ethereal Weapon

R passive armor pen still works.

Mandatory: Vulnerable + Executioner. With Bork, jump anyone — they die; no front-line concept, squishies vaporized. Hexes must have Vulnerable + Executioner; flex rest. Back to Basics and Clown College are huge prismatic upgrades; gold Upgrade Infinity Edge / Vampirism / Transmute Chaos / Soul Siphon all great; silver Adapt / Upgrade Collector / Big Hits / Brute Force / Bloodlust are also solid. Items: Hubris start, then Bork, then Death's Dance, pick from Liandry's / Black Cleaver / Eclipse / Bloodthirster.

Pair with Tank Engine to stack health, then finish with Deathcap and Riftmaker. One W does 100% max HP. Melts tanks.

Use Quantum Computing's huge center-zone physical damage with Pantheon's W (Shield Vault) directional dash to drop enemies into the burst zone. With his ult's passive % armor pen plus lethality items, Quantum Computing can full-HP shred. Flash or Snowball into W to land the target in the 4x center-damage area.

[Hard to scale] Pantheon's W gets bonus health scaling — once you hit ~25,000 HP, W deals 100% max-HP physical damage. Forge: HP > AD. Weak early, scales into tank-heavy matchups; max-rank ult has innate 30% armor pen and his enhanced E grants armor/MR from health.