These arent the only way to show total damage Theme Decks come with paper markers (10s, 50s, and 100s), and many players opt for using small six-sided dice to count, with every pip on the die representing 10 damage
During your opponent's Main or Battle Phase (Quick Effect): You can Fusion Summon 1 "Ninja" Fusion Monster from your Extra Deck, using monsters from your hand or field as material
Use: Great for binder pages, kids picks, or rounding out a Team Up set page
His special effect lets him destroy EVERY enemy monster AND deal FOUR THOUSAND damage to the opponent
It happens again in episode 80 Yuya finally gets to talk to Sora about him getting away when the rest of the cast realized that Yuzu was missing, this scene was played out as Sora running away to avoid capture or being questioned about her whereabouts, but in Sora's flashback of the same events, we see that Sora, (thinking the Obelisk Force had captured Yuzu instead of Serena) went back to Academia to search for her and presumably bring her back to Maiami City, making it very clear he would never let anyone take Yuzu prisoner