Arcade Mode is a brand-new mode, which is heavily inspired by Axie Classic. You can choose to play this mode in the mode selection after clicking the "Play" button in your Origins client. Arcade Mode works the same way as for example Casual Mode or Ranked Mode with slightly less time per turn. Other than that and some special effects that you will soon get to know, it follows the same logic as mentioned modes.
This game mode is using special effects: Class Advantage (yellow icon), Class Bonus (blue icon) and Critical Chance (red icon). You can read more about these effects down below.
Class Advantage
It is sometimes referred as the class triangle (see below). It basically boosts (+20% damage) or lowers (-20% damage) your attacks dependent on the class of your Axie and the class of the enemy Axie.
Class Bonus
Your attack gains +15% bonus damage to the defending enemy Axie when using cards of the same class as your attacking Axie.
Critical Chance
Your attack can gain doubled damage (+100% damage) decided by 10% chance.