Build Challenge: Highest First+Second Round Single Target Damage, No Magic Items/Surprise Round

Level 20 ex-wizard Pit Fiend.
Multiattack once each round. Average 240 damage.

Gtdef said:

DM dependant because I'm not sure about the rulling for contagion. There is nothing in Errata.

Tempest Cleric 15, Sorceror 3, Fighter 2
Contagion Flesh Rot (vulnerability, double damage taken) -> Quickened Call Lightning -> Call down -> Action Surge Call Down
Under perfect conditions, this can do from 205 dmg (target saves against everything, lowest possible rolls) to 600.

Average no save damage is 510
200 (channel divinity + quickened call lightning)
200 (channel divinity + call down)
110 (10d10 average call down)

Click to expand...

Jeremy Crawford ‎@JeremyECrawford
The effects of the contagion spell's disease are meant to activate after three failed saving throws. https://twitter.com/SirJosh94/status/603461998769086464 …
12:23 AM - 30 May 2015

Half Orc Divination Wizard 2, Eldritch Knight 11, Sor 4, Pal 3
Feat: GWM, warcaster; Great Weapon Style
Str: 20, Int 13, Cha 14
Round 1:
Bonus: Quicken hold person. Use portent to assure failed save.
Action: Attack three times.
Action Surge: Attack three more times.
Enemy Goes: Use second portent die to assure second failed save.
Round 2:
Attack three times.
Quicken Booming Blade, Allow concentration to lapse
Enemies Turn:
Enemy moves away, triggering movement damage from booming blade, and another booming blade attack from Warcaster
Total all smites: 98d8 (441)
Total all booming blade damage (9d8 initial, 8d8 movement):76.5
Total bonus damage from str and heavy weapon: 165
Total weapon damage: 31d12 (230)
Total average damage: 839.

{with Haizrawn I think this cracks 1000)