Titans and level 28 Char above Ascalon?

Well I don't know if this is true or not, but I've been told there is an area somewhere north of the General Ascalon area that contains Titans and very high level char...

Is this true? If so does anyone have a map of this place or at least know what it's called?

A quest.

Yes, these are only spawned by a very high level end game quest.

The area is Dragon's Gullet though (past where you get the ashes for that Piken Square quest).

This does contain the highest level normal monsters in Ascalon though. The lvl11 Abominations. Despite their level they are semi-powerful Necromancers that raise lvl13 Bone Horrors and use Shadow Strike.

If you or any member of your party has the "Last Day Dawns" quest, you will encounter them outside of The Frontier Gate. (If memory serves correctly)

Last Day Dawns is a quest you get from Glint in Droknar's Forge after you've completed the story-line missions.

Last Days' Dawn as well as Titan Source both occur in the Ascalon area, and have the high level Charr and Titans. These are both end game quests that, once defeating the Hell's Precipice mission, you can get from Glint in Droknar's Forge.