Axle Tinguard was born in 36 BBY around a month before Ahsoka's birth. He was initiated into the Jedi temple when he was three years old in 33 BBY by Jedi Master Kit Fisto. Ahsoka would arrive within the same week by Master Plo Koon. The two would come to know each other through their youngling classes and become good friends. Axle would be what you would call a star student. Axle would work his hardest every day and would be recognized by the high council.
When the time came for the ceremony for apprentership, both Axle and Ahsoka were at the top of their class. The Jedi high council discussed their opinions about who would be assigned to who. Master Yoda saw the confidence and strength in Axle and even said he would maybe consider training him. However, Master Yoda would decide not to because he did not want to fail like he did with Dooku. Master Windu saw the potential in Axle and after some thinking, he would take him as an apprentice. Ahsoka would later be assigned to Anakin Skywalker a week later because the council thought he would need a Padawan who can keep up with him and help him through tougher times. Also a side note about the council, they hoped teaching a Padawan would help Anakin mature more which was mostly successful.
Master Windu would assign Axle to go along with Ahsoka on many many missions because of their great chemistry together. Even more so than Anakin and Ahsoka. If you ever see Axle and Ahsoka together on the battlefield I suggest either surrendering right away or run as fast as you can in the other direction. Trust me, these two are more deadly than death sometimes.
Axle would learn from a bunch of different mentors because Master Windu wouldn't always have the time for lessons, but Axle would catch on quickly to his own skill sets. He is very talented in hand to hand combat and other close quarters fighting. What is unique about Axle's fighting style is that he combined Jar-Ki form 4 Ataru with Jar-Ki form 6 Niman. He first masters form 6 Niman at the age of 14 and later masters form 4 a few weeks after he turns 15.
Axle and Ahsoka's first battle together would be on Christophsis where they would also meet 501st Captain Rex and GAR ARC Captain Chase and his small unnamed company which they just referred to it as Chase company. After the battles on Christophsis and Teth along with many others, Master Windu assigns ARC Captain Chase and Chase company to be Axle's personal unit. They will go wherever he goes. They would merge with the 501st, 212th, and 91st Mobile Reconnaissance Corp.
After almost a year after the war began, Axle was assigned to go and aid Ahsoka and Anakin to take out the Separatist blockade over Ryloth. Master Windu gifts Axle a heavily armed Jedi Cruiser to help with the battle. Axle later names the large battleship the Predator. The ship will become his flagship and lead many battles including Saleucami, Umbara, Onderon and others.