The battle against the Mad Treant, as it is one of the first boss fights in Ventus's scenario, will test the player's knowledge of Ven's strengths and weaknesses, as well as the game's controls and the mastery of special abilities like Shotlocks. Ventus will have Shotlocks, Command Styles, and D-Links available to him in this battle, so these special powers should be utilized to one's advantage.
The Mad Treant will begin the battle by slowly lumbering around the battlefield. While it is not attacking, rush up to the Unversed boss and attack it with magic or physical combos. Remain cautious, however, as the Mad Treant will proceed to send several bombs raining down in all directions. Chain as many Dodge Rolls together as possible to avoid the attack. The player can then rush up to the boss and attack it, but be careful as it can stomp Ventus if he is too close. Be sure to jump as the Unversed leaps into the air, or else Ventus will be hit by a resulting shockwave. The player should also be careful when it lands as it releases poisonous fruit that leaves purple puddles on imapact with the ground. Touching the fruit or the puddles causes poison status. If the Mad Treant plants its root-like legs into the ground, be sure to remain in the air, or else Ventus will be hit with Earth magic as shards of rock fly up at him.
After taking enough damage, the Mad Treant will collapse, stunned. It will also drop several much-needed HP orbs. Pick these prizes up to replenish whatever HP is depleted from Ventus's HP bar and continue the onslaught. As the Mad Treant recollects itself and its HP starts to dwindle, it will repeat past attacks. It gains one deadly new technique however, one that allows it to shoot three large bombs at Ventus. Dodge Roll to avoid them (they can be seen coming based on their shadows, which appear on the ground as they draw near). The Unversed will continue to use slightly more powerful versions of previously used attacks for the majority of the battle after this, so utilize the same strategies as before to avoid them. So long as the player heals when necessary and attacks only when the Mad Treant itself isn't attacking, the battle should be quite simple to win.