|“||I'm sure everyone wil be fine as long as you're around sir. You gathered all of us yourself afterall. Your dream is to gather everyone under one great power to put an end to all the wars and division. Of course not all of us understand that dream of yours, but everyone stayed by your side and are doing well, sir. Some fell for your power, some fell for your personality and appearance and others just liked you without any particular reason. You may be scary, but amazingly enough, everyone here likes you sir. If you suggest we join the army, we will join the army. If you tell us to die, we will die. If you tell us to live, we will live, sir. Just give us the order. We will always be your faithful servants, Lord Kallavan.||”|
Kallavan is known as the Human Collecter or by his official sobriquet the Human Hunter. This is because he likes to defeat strong opponents, persuade, and recruit them to join his "group". This group consisted of several servants that were divided under 4 known tiers, most likely indicating their "power" and "influence". With 1st tier being the highest and 4th tier being the lowest.
Kallavan's Group were formed long before Kallavan decided to join Zahard's Army. After Kallavan met King Zahard, he had decided to join the army but he still asked for advice or suggestion from Elpathion during story flashback.
After he joined the army, Kallavan was promoted as a Corps Commander and also was given full control and authorities to convert all his servants or followers into joining the army and formed his own private Army Corp, which later known as the 4th Army Corp under Kallavan's command.
After Corps Commander Kallavan failed to kill the Irregular Twenty-Fifth Baam as his secret mission during the Battle of The Last Station, he was demoted to the lowest rank, a mere normal soldier and he also received punishment which ordered him to tie up and seal his left arm with a special restraining device of the Zahard Family. Although Kallavan was demoted, all of his servants' lives were spared and they can stay to serve in the 4th Army Corp under the new command of Po Bidau Lyborick Khun, the newly appointed Corps Commander who were sent personally by Adori Zahard and the army administrative to replace Kallavan.
Prior the Battle of The Nest, Kallavan managed to persuade the ancient hero Dowon to join the army, so he was promoted by Lyborick and his military rank was raised to "Company Commander". With this promotion, Kallavan was accepted back into the 4th Army Corp under Lyborick's command. After Slayer White was resurrected and regained his full prime power in the middle of the war within The Nest, Corps Commander Lyborick finally revealed his plan to Kallavan, Princess Khun Maschenny Zahard and Lo Po Bia Yasratcha, the Corps Commander of the 5th Army Corp, that he want to blow up the main flagship of 4th Army Corp in order to destroy The Cage. Kallavan was very surprised by the order and immediately questioning Lyborick's decision, because it means that most of Kallavan's servants will be sacrificed if they got caught up within the explosion range. Kallavan was very angry and he threatened to kill Lyborick if his plan ended up in vain and gave zero result.
In the end, Lyborick's plan succeed in destroying The Cage but FUG forces suffered no casualties at all because the Irregular Twenty-Fifth Baam managed to save the Canines in very last seconds with the teleportation power of 2nd Thron Fragment, making Lyborick's plan ended up in vain and most of Kallavan's servants died from the explosion.