Looking For Tryndamere Lore

i suggest you wait for his lore update as some things might change but up to this point you can use

http://universe.leagueoflegends.com/en_US/champion/tryndamere/

and for Journal of justice (which is propbly no longer canon) you can use :

http://arcanummajoris.altervista.org/JoJ/Vol1/Issue5.html

as you can see there are different issues and there are more about tryndamere in some of them, but you will have to look trough them yourself since i dont remember which ones were about him.

What Nylisa said - Tryndamere's lore is, for all intents and purposes, obsolete.

It is old and obsolete but here is the abridged version -As a kid his whole village was massacred by some unknowns. He through undying rage killed a few of them. He travelled the land learning to fight through combat became a barbarian king. Ashe nothing his and the strength of those under his banner did a political marriage to him to secure her holdings on the land. It was later revealed that Attrox was there at the massacre and gave trynda his undying rage. If i recall correctly the demon blade trynda represents what will happens should that "Gift" ever surface fully