Walking Dad just posted his character, so he must be (close to) back!
We need to get you finished WD.
For a level 21 Item, might I reccomend a Ring of Heroic Insight (+3 item bonus to Insight checks; Daily Power (minor): Choose a target. Gain a +2 power bonus to attack rolls and a +6 power bonus to damage rolls until the end of your next turn. Vs. an object, gain a +6 power bonus to Str checks to break it. If you've milestoned, +3 to attack rolls and +8 damage/Str checks to break objects.
Other suggestions include Ioun Stone of Sustenance (half sleep-time, no breathe, drink, or eating requirements), or Headband of Perception (+5 item bonus).
You also need some feats it looks like...
How do you feel about Armor Specialization (Scale)? Others that scream "take me!" include Lightning Reflexes, Iron Will, Weapon Focus (Heavy Blades), Armor of Bahamut, Blade Opportunist, Combat Reflexes (I assume, with Heavy Blade Opportunity you ar eplanning on making some OAs?), or Dragonborn Frenzy.
I really like Draxius and the reskinning of Angelic Avenger to Draconic Avenger.
As for who Marks...We should definitely work something out. With lots of enemies, this will be easy, we just each pick a major threat (or a few, depending on our multi-marking ability) and hold them down. I like your idea of alternating marks. I've already used my mark for the round, so feel free to mark over him. I will wait a few rounds to remark him.