He traveled to the world of One Piece and stole the Op-Op Fruit right from the start.

Lynn unlocked the true use of the Operation Fruit.

Observe Germa's bloodline factors, optimize skeletal defense, and master the Corpse Bone Vein.

Observe the weak electrical currents within the body and control the chaotic body movements.

Observe the abilities of the Swallow Fruit, optimize the five internal organs, and master the Six Treasures Immortal Thief.

...

Through the use of the surgical fruit to strengthen bones, skin, and genes, a god-like figure was born.

The most amazing thing is that Lynn can use the Op-Op Fruit to enhance his crew into monsters as well.

Boa Hancock: Ever since Lynn healed my Sky Dragon Mark, I have been Lynn's woman.

Blackbeard: My Dark-Dark Fruit is not the strongest Devil Fruit; Lynn's Op-Op Fruit is the strongest.

Kaido: I am not the strongest creature on land, sea, and air. Lynn is the strongest creature!

The Five Elders: Joy Boy is not the sun god; Lynn is the true sun god.

Im: You're wrong. Lynn is the real god of this world.