Lowkey character that holds back but can really unleash

[Spore]

Greetings playground,

out of the blue one of our players decided he wants to do a modern(ish) magepunk game in D&D 5 (think Final Fantasy 15, https://www.youtube.com/watch?v=htnkOpknGok ) I want a character that is decent and fits in well but has a reason to hold back the majority of his power. Someone who could clearly solo entire encounters but for some reason or another leans back and watches the situation, having the right tool for the right time.

Our group will play with different setups each time so I need a concept that is a bit more independant. We will have a cleric who will mostly likely show up every time but other than that no classes are set in stone nor is it sure that the players can attend the game.

I have had only two ideas so far:

Paladin/Warlock: Some kind of demon hunter who pacts with another demon in order to protect his beloved ones.
Wizard (probably Abjuration or Divination School, maybe Necromancy) as an advisor to an Elder Black Dragon (we met the guy with a group 300 years earlier as a Young Adult Dragon and this would be a great way to link the old and new campaigns)

[MaxWilson]

NG Fiend Pact Warlock. Avoids using magic most of the time because he's not sure what the Fiend is getting out of it and is afraid it most be soul-juice squeezed out of dead souls or something--but since he's not absolutely sure, he will cut loose in order to do clearcut good like save lives.

[Mandragola]

Sounds like maybe a barbarian who could frenzy, but mostly doesn't. Or maybe a bladesinger wizard. Those are two classes that have the option to "turn it on", but don't do it all the time.

A paladin who holds back his spells for smites is another comparable option.

[Specter]

Both Abjuration and Divination are a pain for the DM, according to my own experience.

Well, it seems you want burst abilities for when the going gets tough, so I'd go Fighter/Sorcerer. Action Surge and Quickened Spell (assuming Fighter 5/Sorcerer 3) would give you 4 attacks and a Booming Blade/Green Flame Blade, along with maneuvers or other fighter options, nothing to scoff at.

[BiPolar]

Both Abjuration and Divination are a pain for the DM, according to my own experience.

Well, it seems you want burst abilities for when the going gets tough, so I'd go Fighter/Sorcerer. Action Surge and Quickened Spell (assuming Fighter 5/Sorcerer 3) would give you 4 attacks and a Booming Blade/Green Flame Blade, along with maneuvers or other fighter options, nothing to scoff at.

I like the Divination wizard idea. His rolls are the definition of step in and change the outcome. It's incredibly powerful, always relevant, and only do-able a few times a day. Add Lucky on top of that and you when you want to step in, it's meaningful.

And the brooding wizard that just stands by is a great image :) Or is it mage? muahahahahaa.

sorry. long day.

[MaxWilson]

Maybe combine Divination wizard with Battlemaster? Add in Lucky for good measure.

[Spore]

Both Abjuration and Divination are a pain for the DM, according to my own experience.

Why is that exactly?

Also I do not really care. This might sound selfish (and it is) but the DM has abruptly ended the previous campaign DURING what feels like THE FINALE. I mean come on. The PCs are stranded on the astral realm after my Paladin has destroyed an evil seal keeping the daemonic forces outside of the material plane. We even fled a corrupted mature green dragon. Then we tried to switch to 5e from Pathfinder and the DM stopped because every player wanted a tailored kit for their precious character while I invested time and effort into researching the viable official options for mine.

No one tried, no one cared. So I feel I deserve to be able to use any classes from the CRB. I put more time into the system than the other players combined and will probably need to research all options for all other players as well to guide them towards a fun character so that this campaign might even start. Because people are stubborn and lazy.

Sorry for the rant.

[Osrogue]

Wild Magic Sorcerer for a character who doesn't have full control of their power.

A lycanthrope can trivialize opponents with non-magical weapons, and there is a very obvious reason not to access one's lycanthropy.

It might be what you are looking for, though it might not fit your theme, but that can always be refluffed.

A powered up alternate form seems to be what you are looking for. It's hard to find in a spellcaster, but a barbarian's rage can count as a powered up physical form, maybe through some technological enhancement.

Paladins work as well. Devotion's channel divinity comes to mind+Smites.

[Specter]

Why is that exactly? .

Abjuration because they will dispel/counter anything cast by anyone, and outlast most people in the battlefield with Shield fueling their horrible ward.

Divination because well, Portent.

[Spore]

Thank you for the informative posts so far. I am looking for something the character can CONTROL but CHOOSES not to do it. That's why I really like the idea of

a) A Warlock with Magic Initiate (Cleric) who fled his test to become a Paladin. He had doubt in his heart (and you die in the trials by fire if your heart is unpure). A demon, devil or agent of an elder one festered on his doubt driving him further and further into insecurity and partial madness. He tries to live by the blade and only use the (sparse) Cleric spells he has on offer (if my friend plays a Cleric I will probably focus on the damaging cleric spells instead of the supporting ones). He would be an uninitiated champion of the light led down a dark path by a fiend.

b) A Diviner Wizard with the Luck feat who believes into a set fate for every creature in the universe. Free will is an illusion (yes, it is a nod to Legacy of Kain) and tampering with fate (via Portent and Luck) only leads to a more convoluted way towards the same inevitable death.