Enter the Colosseum, Gladiator beasts

Gladiators are popular because of the Deck’s flexibility. It can deal with all kinds of enemy Decks really well.
Each time a Gladiator Beast monster attacks, it can be returned to the Deck at the end of the Battle Phase to Special Summon another; and when a Gladiator Beast is “tagged in” it hits the field with an additional effect, like destroying cards on the field, or removing cards from the opponent’s Graveyard. Those “tagging” effectsare the basis of the Gladiator strategy.
Gladiator Beast Decks got a boost with the release of Starlight Road. They Set a lot of cards to their back row, so it fits right in to play 2-3 copies of Starlight Road. This protects their set-ups of Traps like Gladiator Beast War Chariot, which can negate monster effects. Another typical play is Waboku, which stops a Gladiator Beast from being destroyed when it’s attacked, but stills means that it “was attacked,” so it can tag out at the end of the Battle Phase.

Old school Gladiator Beast Decks sometimes focused on Elemental Hero Prisma’s ability to mimic Gladiator Beast Bestiari’s name for the summoning of Gladiator Beast Gyzarus. But that strategy hasn’t been very popular this Summer. Most Duelists realized pretty quickly that when you’re Dueling against Infernities and X-Sabers, it’s more important to disrupt your opponent’s Synchro Summons and keep them from putting combos together. That led to a huge upswing in Gladiator Beast use of Thunder King Rai-Oh.