If a character was created years ago, used for a limited time and never seen again, is it okay for a writer to use it and assume the reader needs a back story, or is better to reward reader who their research. Example, Griz, a villain from very short series Slingers, made a reappearance in a Wolverine title. No back story, just a mutant that gets in Wolverines way. Wolverine does what he does best and Griz is left in a pile.

Is using a previous created charter better then making a new character just to be beheaded. Or should this character stay gone?