Is Tiamat Beatable?

[Victim]

It uses the Radiant One ED to add INT to all defenses, Swordmage Warding with the Coronal Guard utility to improve it. I've seen normal ACs of around 50, so with those one time bonuses, it doesn't seem impossible.

 

[Sunglare]

It uses the Radiant One ED to add INT to all defenses, Swordmage Warding with the Coronal Guard utility to improve it. I've seen normal ACs of around 50, so with those one time bonuses, it doesn't seem impossible.

So
Base = +10
Level = +15
Elder Hide armor = +11
Int Stat bonus = +9

Total = 45 AC

I do not have the FRC book but do you get the swordmage warding all the time when you multiclass into it? Not sure what Coronal Guard gives.
You said Radiant one lets you add your INT bonus to all defences but your already adding your INT to AC so you can't add it again.
I know I can squeeze 1 or 2 more points with a feat or shield or so but getting the heavy shield requires at least a 15 str, something a Warlock probably won't have.

 

[Drakhar]

So
Base = +10
Level = +15
Elder Hide armor = +11
Int Stat bonus = +9

Total = 45 AC

I do not have the FRC book but do you get the swordmage warding all the time when you multiclass into it? Not sure what Coronal Guard gives.
You said Radiant one lets you add your INT bonus to all defences but your already adding your INT to AC so you can't add it again.
I know I can squeeze 1 or 2 more points with a feat or shield or so but getting the heavy shield requires at least a 15 str, something a Warlock probably won't have.

He was referring to the Radiant one Utility power that gives you an untyped bonus to all defences equal to your Int modifier, so yes it does get added again, for a total of 54 AC until the end of encounter sans Warding. Multiclassing into a Swordmage gives you a daily warding that lasts until the end of the encounter, which as a Coronal Guard is +4 when a hand is empty, along with the Coronal Guard Utility power which gives you +2 untyped to your AC until the end of the encounter or until you're knocked onconcious. Bingo 60 AC when one handing.

Also as Radiant One is open to any level 21 character, You can be a pure Swordmage and still get your AC that high easily.