DAMAGE ROLL: 1.5 * 10 (bear in mind damage multiplier on a crit is now 1.5 rather than 2) + 3*2 (max enchantment damage and special environmental conditions double this) + 13/2 (DEXmod and rounded up) = 28 dmg
Golem attacks Robert in blind rage! Golem's attack roll = 19 + 15 = 34 Robert's dodge roll = 7 + 7 = 14
Golem hits for.... 13 + 1d3 (3) = 16 - 8 (defense) = 8 damage 11/19 HP left
Robert randomly stabs something with his rapier! Robert's attack roll 20!
Robert hits the golem for 15 (Max weapon damage *1.5) + 8 (DEXmod/2 + STRmod/2) = 23 damage! + 3 * 0 (fire resistance) fire damage from the dragonsteel