Hello, First your going to need Warrior Guild Tokens.
To get Warrior Guild Tokens you will need to go to the room on the first floor with someone in it. Talk to them, and buy rune full helm, platebody, and platelegs. Use any of the armor pieces on the Magical Animator, you will be forced back and the monster will appear. Kill it and repeat this until you have 100+ warrior guild tokens.
Once you Have 100+ warrior guild tokens go upstairs. Talk to the sergeant and you will be teleported into the room. kill cyclops's until them drop a defender. Leave and repeat. You will get better defenders every time you go in.
I hope this guide will help you get defenders.
Sincerely,
Sameblood