Weavile has been with Silver since childhood, when he was a Sneasel. He was one of two Pokémon Silver was known to have while he lived with the Masked Man, and was with him when he was captured. Sneasel would eventually help Silver and Green escape from the Masked Man, allowing them to start a new life.
In Tyranitar War, Sneasel is sent out to battle against Gold and his Sunbo. Sneasel freezes the seed Pokémon with Blizzard to keep her from supporting Exbo with Sunny Day. Sneasel manages to dodge Exbo's Ember attacks, which makes Gold switch out for Sudobo. Sudobo gets the upper hand by attacking with super effective Fighting-type moves, forcing Silver to recall him.
In Delibird Delivery - 1, Sneasel is used to fight against the Masked Man. He and Exbo attack his Delibird and manage to put some distance between the Masked Man and their Trainers. The Masked Man then sends out Ariados and Houndour and Sneasel and Exbo attack with Flame Wheel and Icy Wind. The two Pokémon of the villain's suddenly disappear, and Gold, Sneasel, and Exbo are hit by a minor surprise attack afterwards. The Masked Man then suddenly appears beside Silver, and taunts him by mockingly asking if Green survived when they made their escape, which angers him. Losing his cool, Silver commands a Quick Attack from Sneasel, but neither it nor a Rock Smash succeed in even making a hit. The Masked Man soon flees and Silver gives chase, but he and his Pokémon are defeated.
In Secrets from Sneasel, Silver and Sneasel arrive in their hometown Viridian City. Due to being back Sneasel's memories of the kidnapping begin to faintly come back, and with Yellow's help they manage to recover most of it, which helps Silver figure out who his father is.
In Weavile Wobbles But It Won't Fall Down, Weavile is used to battle against Petrel. Silver has Weavile freeze Petrel's Koffing's vents with Icy Wind to block off it's poisonous gas, but Petrel states that enough of the gas has already been released, and soon enough Silver will fall victim to it. Within the gas Petrel's Raticate strikes Weavile with Hyper Fang and destroys the rope bridge that the group is standing on. Gyarados manages to save them and Weavile goes and holds Petrel at claw-point. Due to his disguise abilities Weavile lets his guard down and Petrel escapes, but not before his Plates are stolen.
Being with Silver since their childhood Weavile has a strong relationship with Silver and cares deeply for him. He is seen alongside him very frequently, often even out of his Poké Ball. Weavile is quick witted and very powerful, often using his speed and cunning nature to outmaneuver his opponents. Like Silver, Weavile can become very dedicated and serious when the situation calls for it.