Fire Truck? (5e Optimized Character Build)
From D&D Wiki
The Fire Truck? is a quintuple multiclass character build that essentially, has a fireman's hose. A blast so powerful it can push you up to 160 feet away. The keystone of this build is eldritch blast, no surprise there. With a couple invocations and multi classing, you can push your enemies up to 160 feet away from you for 5 turns straight.
Choose any race you want. The best options are probably variant human or half elf.
Take 6 levels of warlock. You'll gain 3rd level spell slots through pact magic, the eldritch blast cantrip, and the eldritch invocation repelling blast.
Take 6 levels of cleric. Choose the tempest domain. You'll gain the ability thunderbolt strike which, along with repelling blast, will be a major component of the build.
Take 2 levels wizard. Choose the UA school of lore mastery. You'll gain the ability to change force damage to lightning damage. You can probably see where this is going.
Take 2 levels in fighter for obvious reasons: Action Surge.
Take 4 levels in sorcerer. Take the Quickened Spell metamagic option.
You can switch out your levels in fighter for sorcerer levels. You'll gain more sorcery points but lose action surge.
How it all comes together
You use eldritch blast. At 17th level, you'll conjure 4 beams. Each beam will, because of repelling blast, push the target 10 feet. And additionally, because your wizard levels have changed the damage from force damage to lightning damage, your cleric ability, thunderbolt strike, will take effect and your target will be pushed 10 MORE feet on a hit. That's 20 feet per beam with 4 beams!
On your first turn, cast eldritch blast with your action, then quicken an eldritch blast as your bonus action. Repeat on your second turn. On your third turn, use your bonus action to convert a pact magic spell slot into sorcery points, cast eldritch blast with your action, then use action surge to cast it again. On turns four and 5, you can quicken eldritch blast so you can make 2 castings a turn. So for 5 turns, you will make 8 beams of eldritch blast. Each beam, on a hit, will push the target back 20 feet! If only 2 beams hit, it's likely that the target has no hope of reaching you.
This is the way I'd play the character. Feel free to modify, mix, and match as you want.
Point Buy with half elf ability scores
Str: 15 (for heavy armor. Half elf stat here) Dex: 8 Con: 10 Int: 12 (to multi class into wizard. Will be increased at 5th level.) Wis: 13 (to multi class out of cleric. Half elf stat here) Cha: 17
Cleric. Choose tempest domain. You'll be useless as a caster at level 1, but you'll have proficiency in heavy armor and martial weapons.
Warlock. Gain the eldritch blast cantrip. Choose the fiend to give you some defense against swarms with dark one's blessing.
Warlock. Gain the repelling blast and agonizing blast invocations.
Warlock. Gain pact of the chain to improve your long distance spellcasting by seeing through your familiar's eyes.
Warlock. Increase your charisma to 18 and your intelligence to 13.
Warlock. Gain 3rd level spell slots through pact magic and the invocation eldritch spear. You'll be pushing them so far away, you'll need long range eldritch blast.
Wizard. Choose a couple 3rd level spells that sound nice to you. You'll probably want lightning bolt and counterspell.
Wizard. Choose school of lore mastery. Gain the ability to change damage types.
Cleric. Gain channel divinity destructive wrath. Use when a creature fails the save against lightning bolt.
Cleric. Increase your charisma to 20
Cleric. Gain thunderbolt strike. Each of your three eldritch blast beams will now push 20 feet.
Sorcerer. Choose Wild Magic sorcerous origin, though anything works. I like tides of chaos.
Sorcerer. Gain sorcery points.
Sorcerer. Gain metamagic. Choose quickened spell and distant spell.
Sorcerer. Gain the spell sniper feat and the 4th eldritch blast beam.
Fighter. Choose the defense fighting style.
Fighter. Gain action surge. You now have the 5 turn stream of eldritch fire truck? blast.
Warlock. Gain dark one's own luck to salvage a lost beam.