Hey guys, here's my guide to getting all the defenders.
First off I highly recommend saving the 40 slayer reward points and getting the rude defender from the Slayer shop, it will save you a lot of time getting bronze>rune.
Grab a set of armour (preferably Mithril-Rune)
Then head over to the minigames teleport and teleport to "Warriors Guild"
Then use your armour on the animator and kill it to get the tokens.
Rune drops 80, Adamant drops 60 and Mithril drops 50.
You'll need at least 200 to enter the cyclops room.
Once you're in there you can kill the cyclops until your tokens run out.
Once you get a defender upgrade you'll have to leave the room and re-enter to get the next defender.
I hope you all enjoyed the guide.
Good luck and let me know if I've missed anything.