Mercenary Tao is an Assassin from the Dragon Ball Saga and was considered a gag Fighter up until the recent balancing Buffs gave him an incredible Z-Ability and stats that were a bit more competitive.
EX Merc Tao PUR has one of the highest Critical stats in the game after a full soul boost and all his Abilities also have a consistent focus on Critical Damage. He would have had great Damage potential if it wasn't for the game’s absurd Critical mechanics.
Double Buff Z-Ability
With the recent changes, he not only buffs Base Critical but max Health as well, making him essential for a Purple Color-Counter lineup.
His entire toolkit revolves around Critical Rate and Damage. While the former is Buffed by his Abilities, the latter gets boosted by Extra and Special Moves.
He is a decent last-man-standing type of Fighter as he gets an additional 20% to his Critical Rate. However, this is only useful when paired with the Critical Damage buff from his Extra or Special Move.
Ineffectiveness of Critical
The way Critical Rates are handled by the game renders this mechanic almost useless. The base rate is 3% and further increased based on the ratio of Teammates’ and Enemies’ Critical.
In most cases, EX Merc Tao PUR sees only a slight increase to 5%-6% Critical Rate which is insignificant.
Held Blast Arts Cards
His already low Blast Attack stat is made even worse with two held Blast Arts Cards. This heavily limits his Damage output unless there's another Teammate with two Strike Arts Cards.
Lack of Tags
The absence of proper Tags not only locks him into Color-Counter Teams, but he also suffers from a lack of Equips.
He is a crucial bench Fighter for sure, but it’s hard to recommend him as a Core Fighter. At most, he is a decent third Fighter for times when the Enemy lacks a Yellow Fighter.
Dragon Ball Saga
There are quite a handful of Fighters from the Dragon Ball Saga, albeit only two of them carry a relevant Z-Ability. Hopefully, more of them will be added in upcoming updates, making this Team more viable.
The balance gave his stats a major Boost and even improved his Z-Ability to make it more viable.
His toolkit is primarily focused on Critical Bonuses which isn’t a very useful stat beyond Boosting the Team’s overall power level when Soul Boosting.
The way Critical Damage works in Dragon Ball Legends makes it not worth the resources put into improving that stat. This means that for Fighters whose entire toolkit revolves around Critical are by default less useful in Team Building.