This is
@Goldfish's plan, but it starts with massive explosions instead of wrapping a fucking towel around its head. And if this super-duper magic sword doesn't already bypass DR, then it doesn't deserve its hype.
[X] Plan boom
-[X] "Dance with me, then"
-[X] Waymar uses his Temporal Acceleration crystal as a Swift Action to gain the effects of Time Stop for two rounds.
--[X] First turn of Time stop : he moves up, puts an Explosive Launcher Round on the ground next to (or behind) the enemy. He uses his swift action to cast a Quickened Protection From Energy (cold) on himself. If he already has such an effect active from pre-mission buffing, he instead cast a Quickened Find the Gap on himself.
--[X] Second turn of Time stop : he puts another Explosive Launcher Round on the ground, and steps back out of range. He uses his swift action to activate his Belt of Battle, for another Full Action.
--[X] He uses his real turn's standard action to shoot his last Explosive Launcher Round, to detonate all three in the target's face. He then uses his real turn's move action to get back into melee.
--[X] Finally, he uses the Full Action from his Belt of Battle to use a Hasted Full Attack. He activates his Arcane Strike ability using a 4th level spell (+4 bonus to attack rolls and +4d4 damage per attack this round) as a Free Action before attacking. If at any point he needs it to save his life or avoid defeat, he will use his Fate of One crystal as an Immediate Action to gain a reroll.
Edit : This plan assumes that a Launcher is like a crossbow, and that you can't Full Attack with it. Is that correct?