Aqui vai a minha build de Rogue. O dano no primeiro round é muito bom, mas ele é totalmente dependente de sneak attack. Algo que infelizmente não dá pra garantir (precisaria de pelo menos um aliado batendo antes no tarrasque).
Ao calcular as médias eu arredondei algumas para baixo (d4 para média 2, 3d6 de 10.5 para 10, e sneak attack 9d6 de 31.5 para 31). Assim o meu "azar" de sempre fica contabilizado nas médias.
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Halfling (Stout) Revised Ranger 3 / Rogue Thief 17
Str 10 (29)
Dex 17+2 (race) = 19 +1(feat) = 20
Con 15+1(race) = 16
Int 14
Wis 16
Cha 12
Feats: 4 - Athlete / Squat Nimbleness, 8 - Luck, 10 - Dual Wielder, 12 - Magic Initiate (Wizard), 16 - Blade Mastery.
Ranger: Favored Enemy Monstrosities, TWF fighting style, Hunter Conclave: Hunter's Prey - Giant Killer.
Items Attunement: Cloak of Displacement, Rapier +3 Energy x2
Items: Leather Armor +3,
Spells: Hunter's Mark (concentration, +1d6 damage)
Potions: Speed (+2 ac, adv dex saves, +1 action), Heroism (+1d4 attack roll & saves), Giant Strength (str 29), Potion of Growth (+1d4 damage, adv str saves & checks), Potion of Acid Resistance.
Attack roll: +6 (prof) +9 (str) +3 (magic weapon) +1 (feat) +1d4 (potion of heroism) = 19+1d4
AC: 12 (studded leather) +3 (magic armor) +2 (haste) + 5 (Dex) +1 (Feat Dual Wielder) = 23
HP: 10 (1st level ranger) +6x2 (ranger levels) + 5x17 (rogue levels after 1st) + 3x20 (Con) = 167
-- Damages:
Normal Attack: Booming Blade = +3d8 (spell thunder damage)+1d8 (rapier)+2d6 (energy weapon)+1d4(growth)+1d6(hunter's mark)+9 (str)+3 (magic weapon)+2(favored enemy) = 4d8+3d6+1d4+14 = 18+10+2+14 = 44
Off hand Attack: +1d8 (rapier)+2d6 (energy)+1d4 (growth)+1d6 (hunters mark)+9 (str)+3 (magic weapon)+2(favored enemy) = 1d8+3d6+1d4+14 = 4+10+2+14= 30.
Haste Attack: (same as off hand): 30
Sneak attack: 9d6 = 31
Total damage (1st turn) = 44+30+30+31 = 135
Second Turn Thief (same damage as 1st turn) = 135
Reaction Giant Slayer (if attacked by a Large or Larger opponent): Normal Attack + Sneak Attack = 30 + 31 = 61
Total First Round: 331.
Second Round: 135 (1 turn of attacks) or 196 (if giant slayer is used)