Former Archmage

Once, you were an Archmage.  No magical working was beyond your grasp, and your reputation was legendary.  For centuries, you traveled about your world, gathering bits of sorcery and helping anyone in need. You were part of a community of the greatest heroes in the history of your world. Your legend was already graven upon the minds and history of most of the peoples of your planet as a friend to all, and an enemy of evil and suffering.   You were known as "The Good Man", "The White Wizard", and "The Sainted Sorcerer". You even had a small following of worshippers, although you discouraged them as gently as possible they you encountered them. 

Then, The Bloodwar came.  
Some evil mage attracted the attentions of The demon prince Orcus, , and when it tried to gain a foothold in your world, one of its infernal counterparts from the Nine Hells moved to thwart its ambitions, and the ensuing conflict quickly escalated to the point where Hordes of demons and devils were pouring into your plane in an ever-increasing torrent.
For 50 years, you and the other heroes  of your world fought to stem the tide of destruction, but to no avail.  As your allies fell, one by one, your anger and bitterness grew.  Finally, the few of your group left recognized that all was lost.  Some wanted to end their own lives, or flee to alternate Prime material planes, but you had other ideas.
You convinced your fellows to mount an expedition of vengeance against the Demon Lord Orcus, who had led the demonic hordes into your world to begin with.  And soon about a dozen of the most powerful mortals ever to exist in any plane were fighting their way through layers of the Abyss, making their way toward Orcus, one battle (and casualty) at a time. 
After months of near-constant fighting, the remaining 5 stood at Orcus' gates and launched the assault.
You nearly made it.  
Your party made it all the way to the throne room, where they were fallen upon by the legions of succubi, and your comrades fell one by one, their life energy drained from them by the foul Demons. You yourself were the last one standing. Your Staff of The Magi  had kept you alive, although your life energy had been drained to the point where you could barely cast a cantrip.
And Orcus sat on its throne, and *laughed*.
In a white-hot fury, you lept at the vile thing, and knowing that it probably meant your death, You snapped the overcharged Staff over your knee, unleashing all its pent-up charges in a Retributive Strike, right in the thing's face. 
As the titanic explosion shredded your enemy's flesh, a hole was torn in the fabric of reality, and you were unceremoniously pulled in, and cast through the multiverse.
you hurled through millions of realities in seconds before a thin spot opened before you, and you were hurled out into a strange sky, on fire; blazing like a comet under unfamiliar stars as you fell into a lake below.  You were found, barely alive, by human fishermen, who spoke a strange dialect of the common tongue, heavily influenced by Elvish.
You are now in a strange land, with its own strange brand of magic.  You have no home to return to; no friends, no family, and you are oh, so old and tired.  
But the need for vengeance still burns bitterly in your soul.   You have a few magical trinkets and abilities that still seem to function.  If you can find a local mage and prevail upon  them for few spells, perhaps you might manage to make a life here.  Because these poor souls have no idea how lucky they are to have a home.  And how quickly that home can be destroyed.

Skill Proficiencies: much of your scholarship is useless, but some skills are universal.

Tool Proficiencies: You still retain a number of useful crafting skills

Languages: You can communicate in the common tongue, barely.  Fortunately, you have two permanent enchantments that still seem to operate.  Tongues, and Comprehend languages.  essentially, Any creature you speak to hears your words in its native language, and you hear their words as your form of common tongue.  You can read any written language, but cannot write in any that you do not already know.  Fortunately, some languages are the same across many planes and dimensions.

Equipment: You retain a few magical trinkets that somehow still function:

Suggested Characteristics

- I am the last of my kind,  and the Demons will pay dearly for every life they've taken
-This plane doesn't realize how fortunate it is,  There is deadly peril always just a thin dimensional barrier away
-When you get to be my age, *then* you can tell me what to do!
- I Hate fiends of any sort, including Tieflings.  disadvantage on charisma checks with them,  because my loathing is too powerful to be kept hidden

d1	Personality Trait
1	-When you get to be my age, *then* you can tell me what to do!

d1	Ideal
1	-This plane doesn't realize how fortunate it is, There is deadly peril always just a thin dimensional barrier away

d1	Bond
1	- I am the last of my kind, and the Demons will pay dearly for every life they've taken

d1	Flaw
1	- I Hate fiends of any sort, including Tieflings. disadvantage on charisma checks with them, because my loathing is too powerful to be kept hidden