Was Crocodile stronger at Marineford? Or was he holding back in Alabasta?

 During the Alabasta arc, Crocodile displayed a level of power that was initially considered overwhelming by the Straw Hat Pirates. He possessed the Logia-type Devil Fruit called the Suna Suna no Mi (Sand-Sand Fruit), which granted him the ability to control and transform into sand. He had a reputation as a Shichibukai and controlled the desert kingdom of Alabasta from the shadows. His strength was showcased through his battles with Luffy and others. At Marineford, Crocodile was present as part of the war that took place at Marine Headquarters. While he did participate in the battle, he didn't display the same level of dominance as some other powerful characters present. This has led fans to speculate that he might not have been as strong as initially portrayed in Alabasta. It's important to note that power scaling and character abilities can be subject to interpretation and development by the author. Oda often keeps details deliberately open-ended to keep the story intriguing.

Did Tolkien abord the relationship between Manwe and Melkor?

 Yes, J.R.R. Tolkien explored the relationship between Manwë and Melkor in his works, particularly in The Silmarillion. In the mythology of Middle-earth, Manwë and Melkor were two of the most powerful Ainur, or angelic beings, who were created by Eru (also known as Ilúvatar) before the creation of the physical universe.

Manwë was the most powerful of the Ainur and was responsible for the creation and governance of the physical universe. He was the ruler of the Valar, a group of powerful Ainur who were tasked with shaping and protecting the world. Manwë was a benevolent and wise ruler, who worked to bring order and beauty to the world.

Melkor, on the other hand, was the most powerful of the Ainur after Manwë, but he was also the most rebellious and corrupt. Melkor was jealous of Manwë's power and sought to challenge his authority. He often acted against the will of Eru and caused great harm and destruction in the world.

Despite their differences, Manwë and Melkor were bound by their shared origins as Ainur and their mutual love for Eru. However, their relationship was strained by Melkor's rebellion and desire for power, which ultimately led to their opposing roles in the shaping of the world.

Overall, Tolkien explored the relationship between Manwë and Melkor in his works, particularly in The Silmarillion, as a way to illustrate the themes of power, authority, and rebellion in his mythology.