Tabard of the Lightbringer is one of the tabards which appeared in WOW at 80 levels, it is a tabard with a very shiny on-use effect.
The tabard itself displays the presumed symbol of the Knights of the Silver Hand. Players who have the tabard normally have the legendary weapon Shadowmourne - the strongest two-hand Axe in 80 levels. Players who can use two-hand Axe when enter ICC will get a quest when gaining a certain reputation. Completed some quests they will get a quest to collect Shadowfrost Shards*50, completed the quest will received Shadowmourne. Maybe it takes two months, not only Shadowmourne you will reward but also gain the following after killed The Lich King with Shadowmourne: Jaina's Locket, Sylvanas' Music Box, Muradin's Favor, Tabard of the Lightbringer, Reins of the Crimson Deathcharger, very useful toys and wow mount.
And now, you can purchase these items through AH by WOW Gold, like toys,  WOW Mount, even the most popular Tabard of the Lightbringer. This kind of tabard with "on-use" effect is rare in the game but looks brilliant.
May the light always shine with you!