Po Bidau Gustang/History

History
Eurasia Blossom and Gustang were lovers for a period, yet both splits after the infamous Eurasia Enne Zahard incident (Enne Zahard was the daughter of Blossom and Gustang. Blossom was very opposed to her becoming a Zahard Princess). After splitting with Blossom, acting contrary to his reputation, he started to go out with different women. However, his greatest followers took his side and stated that he was acting up because the empty spot where Blossom once occupied was too big. Of course, when he went from a "nice guy" to a "bad guy", his popularity increased even more.

At some point, Gustang proposed to Zahard to choose exceptional female children who will be gradually injected with Zahard’s blood and let them compete with each other as they climb the Tower. Of all these women, the most talented of the surviving princesses would become Zahard’s wife. And thus the system of the Zahard Princesses came to be. However, as the competition intensified, the relationship between the 10 Family Heads also started to turn sour leading to discord between the Families.

Tower of God: Part 2 - The Workshop Battle
Before the Workshop battle began he was "coincidentally" assigned as the head of the E-rank Workshop Battle instead of a Great Teacher, overseeing everything onboard the Archimedes. He made a brief but unofficial appearance at the beginning of this arc where he could be seen smoking and sitting next to a CD player. A voice emitted from the player and asked if the man had an answer to his question. Gustang didn't answer directly, instead saying that there was still lots of time, as the game had just started.

Thorn
Gustang made another appearance, talking again with the person from the CD player. The man from the machine stated that he allowed Gustang to control the Workshop Battle however he wanted and asked him about his plan. Gustang replied that he will watch how the boy dealt with the hardships as long as the competitors didn't cross the line while seeing how strong the "real Thorn" got when it was in the hands of an Irregular.

Closure
As Androssi rescued Baam, Khun, and Rak from the dissolving solution with Bon Bon, Gustang approached Madoraco. When the latter noticed the former's presence he ordered his Rankers to withdraw and abandon the Thorn, otherwise, Gustang would destroy their trade business.

Madoraco asked when he began to play on the palm of his hand while also guessing that he was the one who gave FUG Enryu's Thorn, to which Gustang replied that he was only at Archimedes "coincidentally" as the head of the Workshop Battle in place of the Great Teacher, only restraining Madoraco for a fair game.

Later on, Gustang was discussing with his unknown associate, who then asked the Family Head "who was the 'real' Zahard's Prince that will take the Tower's last test?". Gustang replied that the person was impatient and that 'their' adventure had just begun.

The Floor of Death
Gustang is revealed to be the person that helped Garam Zahard escape from the Zahard Empire by setting up the Floor of Death and keeping information away from Zahard.

Gustang appears in front of White and Karaka while they try to leave the Floor of Death with all the souls from the Spirit Room, his very presence pushing White down and recognized as the Head of the Po Bidau Family as White knew the power of the 10 Family Heads. He muses on how the Arie Family was never known to teach how to be a thief and doesn't even bother to stop White from trying to escape, as it is impossible since he has bound himself to the Floor by consuming souls that were cursed, while mocking him for his inferiority complex towards his father having put him in a hell that he cannot escape. After White was finally exhausted by his failed attempts, Gustang pities White for how his desire for power lead to his state before proceeding to remove the stolen souls from White but spares his life.

After having a talk with Urek about returning the souls to the Spirit Room, Gustang notices Baam and calls him Son of Arlen, claiming that he was waiting for him. With the souls safely returned, Gustang and Baam have a talk. The Family Head expresses shock that Baam isn't aware that he definitely knows Arlen as he is one of the Great Warriors and notes that he was on good terms with Arlen as her easy-to-get-along nature made it easy for him but he shows nothing but disgust and anger towards Baam's father, saying that all he has to say about him is just that he's the worst person he ever met. Gustang offers Baam a favor with his expertise in science and medicines and at Baam's request, he cures Rachel of a deadly poison with just a gaze.

Gustang informs Baam that he has a test for him and in exchange, he will give him the second Thorn fragment. This test is to recover an Item from a place called the Hidden Floor. Gustang explains how the Hidden Floor works and that the Data of a Younger Zahard is protecting it. As Baam accepts the offer, he asks Gustang to lift the spell on the Floor of Death but Gustang reveals even he cannot remove the spell as it's difficult for even him to remove lesser but completed spells and even if he could, he won't since it would put Garam in danger and puts Baam in his place by reminding him how the inhabitants actually want to stay there to not die. Gustang then confronts Urek and lectures on how far beneath Joe is compared to him, much to Urek's distaste, and reminds Urek that what Garam wants from him is the death of Zahard so he shouldn't do it and offers to spare Joe from having his memories erased but Urek tells him to erase Joe's as well, mocking Gustang's earlier words.

At the end of the arc, Gustang has a conversation with a mysterious person about the events that just unfolded, saying that Urek Mazino wasn't going to be a problem. He further informs this person that he gave the second Thorn to Baam and a gift to this person's "pawn" who turn out to be Rachel.

The Last Station: New Wave
After the Battle of The Last Station ended, Po Bidau Family Mothership sudddenly appeared in front of Ha Cheonhee's squadron, blocking their path. Gustang was seen aboard the massive Floating Castle with a group of people by his side. The Messenger from the Po Bidau Family then appeared as representative to explain the situation to Cheonhee. In the end, Gustang rescued two hostages, Rachel and Yura Ha from Cheonhee's warship because he wanted to retrieve the 3 precious items that were stolen by Treasure Eating Stingray, those items are Zahard's Bracelet, Wangnan's Ring, and one unidentified item. Gustang then said he will grant three wishes that Rachel wants, in exchange for the three gifts she collected for him.