18,000+ weight Silligie
Silligie can reach 18,062 weight with double Cow plushies + Weight VI + Guard pack role, and the use of it's Fortify ability. Traits used in this build are Weight VI (fully upgraded weight) + Damage I, screenshot was taken during a blood moon. If I'm not mistaken this is the heaviest flier for it's speed class, I know Gimon-Ogu is technically considered a flier and is a worthy contender but it has the slowest flight speed in the game and only has 15,250 weight fully grown so this manages to outclass it in both weight and speed. If I'm not wrong this has the potential to be one of the strongest fliers, no? it's bulky enough with it's weight and guilt ability that it can survive any interaction long enough to escape if it doesn't win and can dish out lots of damage thanks to it's weight and ailments to anything that weighs less than it making it extremely hard to kill, it's become my go-to flier.