Under D&D rules, a dagger does 1d4 base damage. The average human has a Strength score of 10, adding no bonuses. Several of them, due to the military background of many, likely had strength or dexterity scores of 11-14. But only two or three, and quite a few would be frail with old age, sinking to 8-9 strength. All in all, we can only add a total of +1 damage per round from Brutus.
An estimate of sixty men were involved in Caesar’s actual murder. Not the wider conspiracy, but the stabbing.
Julius Caesar was a general, which is generally depicted as a 10th level fighter. Considering his above baseline constitution and dex, weakened by his probable history of malaria, epilepsy, and/or strokes (-1 dex modifier), and lack of armor at the time of the event, he would likely have something along the lines of AC 9 and 60 HP. The senators would likely hit him roughly 55% the time.
So the Roman senate had a damage-per-round of 66, more than enough to kill Caesar in one round even without factoring in surprise round advantage.
There are actually a couple bits here that I have to question. Firstly, I think it’s safe to assume Julius Caesar was flat-footed at the time, meaning his dex modifier isn’t counted in his AC, bringing it back up to 10. This is also not factoring in the probable class ranks of the senators, many of whom I would personally assume have at least two levels in rogue, giving them +1d6 sneak attack damage. If we’re giving them the benefit of the doubt and say that only 10% of them were underhanded enough to have class levels specifically for sneak attack bonuses, that’s an extra 21 damage per round on average against a flat footed and unaware opponent, which we’ll call 10 extra damage after accounting for the fact that half of them probably miss. Brutus likely has a leadership feat that gives a morale bonus, let’s say +1 to damage and saves against not committing regicide. That’s an extra 60 damage, or 30 after accounting for who missed and who hit.
So that’s 106 damage, give or take, in one round of combat. But Caesar has to live for at least one more round, so Brutus can be the last one to stab him (see rules for coup de grace).I think the need for that extra combat round is a strong argument against the 60 senators rising above a mean 10 average in all stats, or Caesar being over 10 character levels; even if we only assume 8 of them got attacks in on a gridded system (and I agree, Brutus’ majesty deserves a possible Bless-style bonus), our AC 10 Caesar is going down quick, 2 rounds at best.
No, no, no. Caesar was at most 5th level, probably 4th. 60 HP is ridiculous; a man with 60 HP can do a trust fall off Trajan’s column, splat, then stand up and walk it off because that only dealt 7d6 (20m ~ 65 ft, 1d6/10 ft) and so the worst case is 42 damage and 18 HP remaining. Anime protagonist Julius Caesar can probably pull that off, but ordinary man of great areté Julius Caesar, or even hero of epic poetry Julius Caesar, cannot. (Points of comparison: Odysseus probably was 5th when he left Troy and picked up a level or two on the way home. Aragorn, son of Arathorn, High King of Gondor, is 6th level at most, and whether it’s mano a mano or arma a arma I bet on Aragorn over Caesar.)
So yes, Caesar is a career soldier, near the peak of human performance; he’s 4th or 5th level. He was once an extremely fine specimen (probably the Elite Array, 15 14 13 12 10 8) but at 55 he’s passed middle-aged by Roman standards and is solidly old (-3 to physical stats, +2 to mental ones), plus his training over his career (i.e. +1 to an ability at 4th) he probably now has +2 to int, +2 to cha, -2 to dex, and +0 to everything else. So he has 27-32 HP if he rolled normally, 50 if he rolled perfectly for health.The Senate is all rich and well-doctored, so they probably wouldn’t have much worse stats than him. But they’re mostly not soldiers, all of them are at least middle-aged, most of them are old, and some will be venerable (70 years or older). But probably the venerable senators will mostly not join in the stabbing, so we can round it off to half middle-aged, half old and call it good. So they’re about evenly split between -1 strength, +0, and +1; 3 of them deal on average 7.75 damage between them. They all have a couple levels of aristocrat, so their attack modifiers will range from +0 to +2, so they’ll hit 60% (=12/20 = 36/60) of their attacks and get 93 damage on average. That’s wrecking him to a bloody pulp.
No, what actually happened was that they all pulled their punches. They specifically wanted everyone to be involved in the stabfest, so they each dealt minimum damage (this is allowed, if you’re taking your time, which they were). This means that more of them will hit (75%). They still deal more than enough to kill him dead; that’s still 45 damage, enough to bring from from 32 to -10. Put Brutus at the back of the line and that’s just about exactly enough to finish him off as viciously as possible in one round.