Paul Wan is the owner of the "Honkytonk" café the Get Backers also use as their place to hang out and as their "operational basis", so to speak. Ban and Ginji always have unsettled tabs with him, and sometimes forces them to work off their debt or refuses to give them food. Although the Get Backers knew it all along since they took over their job from the first generation, it is only revealed very late in the show that the friendly and almost shy Paul was one of the first generation Get Backers, together with Midou Ban’s father, whom Paul shared a similar relationship with like Ban with Ginji now.
Upon his return to Ura Shinjuku, he set up the Honky Tonk, and handed the name of the Get Backers to 3 youths. His vast network of connections may be through these "second generation" Get Backers, who had passed down the name to Ban and Ginji. Eventually, he had two assistants under him: Natsumi Mizuki and Rena Sendou.
He is sort of a philosophical father-figure in the series. Later in the manga, it is revealed that Paul, along with Ban's father, were the first generation of Getbackers and they had, in their time, ascended to the top of the Infinity Fortress, even entering Babylon City. However, neither can remember their time there as a result of the seal, which the "stigma" eye gained at that time, placed on the memories of that time. In his fight against Shimon Miroku (the Miroku 7's father), he once reverted back to his younger self (during his days as a GetBacker), when he was stronger physically. But, alluding to the wise words he has given to others, he realised that his true strength lies in the wisdom he has discovered in himself since the time he set up the Honky Tonk.
In the anime, Paul's background is revealed in episode 42, and is quite different from the manga. Here, he was once part of a trio of thieves.
Although he basically has retired, a last job of the current Get Backers requires the involvement of Paul, who is not in his prime anymore but hardly to be underestimated. Being the "Gale Emperor" he controls the powers of the wind.
During the confrontation between Der Kaiser and Paul, they have their famous ‘unmoving’ battle. Both face off several meters away from each other, Ban and his friends are wondering why no one makes a move when. This is when Akabane throws in a rock that immediately gets cut in two once it reached a certain radius. It is only then that it becomes apparent that Paul and Kaiser move all over the place while appearing to stand still to the likes of Ban and Ginji.
After a couple of blows being exchanged, both go all out to finish it, which brings almost the entire room down in rubble and pieces. The fight gets interrupted however, when Ban steps in to stop his father.
Paul bears the Stigma eye, like many other people, a sign for his power and how far he has reached in Mugenjou back in the old Get Backer days. Being able to revert back to his "prime days" Paul can also become his younger self again and access incredible power and speed.
Paul controls the winds as his primary ability. Along with his great speed, this earned him the nickname, "Gale Emperor" (ｾﾌ､). Given his off peak condition, he could still beat off Der Kaiser's henchmen easily, something which the GB duo couldn't do initially. During one fight which showcases his top form in his youth, a mere walk from him can generate a vacuum so strong it could cut people like knives and render them unconscious or literally cut people into pieces.
Paul Wan has the ability to revert back into prime days form. This allows his power to be at his peak. However, when facing one of the "Drei Ritter", the bodyguard to Der Kaiser, Ban’s father, he was still beaten. Paul then reverted back to his current self and made use of his glasses he wears all the time. The glasses are completely opaque (meaning that he is completely blind while wearing them), forcing Paul to rely on his instincts and experience. He is able to negate all damage done to his inner body. Only the outside of his body will be damage, but no internal and series external damage will happen to him. Ex. He is able to get slashed and stabbed by Shimon's sword and not receive any damage that would injure him. His body may be covered with scars, but all of his vitals points and etc are protected. Also, he is able to fight without the uses of his 5 senses, but with instinct alone. With this, he is able to grasp where his opponent is going to attack and how. He is able to see through his opponent's strategies and skill. Knowing that wisdom is a more powerful weapon than youth and strength he managed to defeat Shimon Miroku, the father of the Miroku 7 and strongest of Der Kaiser’s guards.
As mentioned earlier, his speed is a dreadful weapon indeed. It allows him to move at unthinkable levels. With a mere foot step Paul can cut his opponents to pieces. He is able to move so fast that even for the schooled eyes of Ban and Ginji; everything appeared as if Paul wasn’t moving one inch while exchanging dozens of blows within seconds. During his battle with Shimon Miroku, the two moved at such speed, that while everyone was watching them fight, it was revealed that they were merely watching afterimages of what was happening before. Paul and Shimon were delivering dozens of blows while it only seemed as if they were hitting each other once. Paul and Shimon were moving so fast that while everyone was trying to grasp their battle, they could only see what was happening seconds after their attacks. Ex. If Paul was being stabbed by Shimon, and then Shimon only saw an afterimage, and Paul was behind Shimon read to attack, the spectators would just be seeing Paul about to get stabbed.