Arlo was the third and final Team GO Rocket Leader encountered by one of Professor Willow's assistants. Prior to joining Team GO Rocket, Arlo was a member of Team Valor and a close friend of Candela, but suddenly left some time after Candela became the Team Valor Leader, and she had not heard from him since. While researching at a field with Professor Willow, Candela spotted Arlo at a distance, surrounded by a large group of his Shadow Pokémon. Considering Blanche's and Spark's earlier encounters with the other Team GO Rocket Leaders, Candela and Professor Willow retreated back to the lab, seemingly unnoticed by Arlo.[1]
Arlo is known to be sly and manipulative. After joining Team GO Rocket, he has contributed to its Shadow Pokémon program. Apparently, Arlo turned to Team GO Rocket because it was able to offer him what Team Valor could not.[2]
On November 5, 2019[3], Arlo sent the following message to Candela:
"Candela. After all this time, you still haven’t changed. Tsk.
Remember, fire is a fickle thing. When controlled, it provides warmth, but in the wrong hands, it burns.
You will regret the day you took what was rightfully mine."
On July 26, 2020, during Pokémon GO Fest 2020, Arlo battled Candela. Candela initiated the battle by sending out a Rapidash, while Arlo sent a Shadow Scizor.[4] While Scizor was using X-Scissor, Candela reminisced about the time both Arlo and her were training together with their respective Scyther and Ponyta before parting ways. Coming back to her senses, she commanded Rapidash to use Fire Spin.[5] In the end, Candela won the battle when Giovanni recalled Arlo to him along with the other Team GO Rocket Leaders.[6]
Arlo uses a team of three Shadow Pokémon in a Trainer Battle, each independently and randomly selected from separate pools. Green-colored cells denote the Pokémon that will be encountered during the bonus challenge. The Shadow Pokémon left by Arlo all have a chance of becoming Shiny, as denoted by the icon.