If I delete some characters, can I get them back indefinitely?

Hi all.Returning WoW player here. I initially set up on Grobbulus when TBC Classic first launched, but some returning friends are wanting to play & they want to play Alliance. Understandably since Grobbulus is a PvP server, I cannot make Alliance characters on the server.My question is, is if I delete my characters on Grobb & don't recover them for quite some time, can I still get them back at a later date, or are they gone into the nether forever? I worked really hard on my hunter, and honestly would like to continue playing it (may just server transfer it, but, GrobbMob baby...) and would hate to see it go.​Thanks!