Brock

Brock was a former travelling companion of Ash, who traveled with him through Kanto, Johto, Hoenn and Sinnoh. He was voiced by Eliud Munoz.

History
Brock first appears in Ash Ketchup Vs. Dawn, where he referees for Ash and Dawn's battle.

He is seen yet again in Ash Ketchup Vs. May as he watches Ash and May's battle along with Max and Pikachu.

In Time Flies, Brock is seen in the background with Pikachu, watching as Ash and Dawn argue about raising Piplup. Later in the same episode, Ash tells Rowlet that he should introduce him to Brock at some point.

Brock made an appearance in a flashback in Ash Ketchup Remembers Charizard, where he is seen along with Ash and Misty travelling through Kanto.

Appearances
Time Flies (flashback; mentioned)

Shorts
Ash Ketchup Remembers Charizard

Other
Ash Ketchup Vs. Dawn

Ash Ketchup Vs. May

Trivia

 * When Ash mentions his friend Brock likes sacks like Rowlet, it is a clear reference to 1KidsEntertainment's Pokémon 'Bridged version of Brock.