Starting haki training.

Gem could also exist outside of his body in a soul form. His appearance wasn't much different than the original Brook in this regard. Though, he couldn't travel very far using his soul form. He could only travel about ten meters. He tried increasing his range but was unsuccessful.

Though he did gain a separate ability then that of Brook it was the ability to separate his soul into smaller parts. He could separate about three different soul wisps from his body.

One of the uses of this ability was by using it he could separate his body part along with his soul. He could separate a hand from his body and control it from afar.

His ability was like a wireless connection whereas Brook had a LAN.

Most of the time was spent trying out this ability as it was fun and interesting to use.

Another use of this ability was by imitating the movement when throwing a knife, he could send his hands and fingers flying to the target and recall them back to him.

By diligently practicing he had already become a master at using the abilities he developed.

Due to not having an enemy to battle with he didn't know the exact effectiveness of his ability. This led to him reaching a bottleneck, he had yet to find other ways to use his devil fruit, and he already mastered the use of his current abilities to the best of his ability.

Reaching a bottleneck in his devil fruit training. He decided to choose another path to master. The only remaining thing he could do was to either increase his weapons, and martial arts mastery or learn haki.

In regards to weapons mastery, he couldn't do much, there wasn't a weapons manual he could learn from nor was there an opponent who could help him develop his ability.

Similarly, in the case of martial arts, he was not sure if his body could even master the navy's six styles. Though, he has plans to try them regardless. He also hope to try other famous martial arts such as fisherman karate and Hasshoken in the future.

He believed he had finally found a way to learn armament haki. But, to learn armament haki, he first needed a sustainable source of growth and healing for his damaged bones, as to learn armament haki he had to break his bones continuously.

So he decided to eat calcium-rich food. It would be best to drink milk as shown in the show. Milk was able to immediately grow broken bones and teeth. But it was impossible to find milk in the middle of the Florian triangle.

Fortunately the only source of food available 'Fish' was a calcium-rich food.

He first cracked the ulna bone by hitting it with his cane there wasn't a big crack but a rather small one. He then ate a fish whole with the bones. His bones slowly started to heal. Eventually, it took about half an hour for the broken bone to be fixed as well as before.

Finding a solution to one of his more serious problems, he started actively hunting fish using knives. After hunting for a month his kitchen hall was filled with fish. There were all kinds of weird-looking fish from big to small. All the fish were frozen using his ice ability to prevent decay.

Done with all the necessary preparation he decided to start his haki training.

Uh, more than calling it training it was rather, Gem repeatedly striking his body with his cane. Much to Gem's surprise the broken bone hurt extremely bad, to the point that it was almost unbearable, he had rarely faced such pain throughout his life.

In his initial days of training, he gritted his teeth and broke a few bones at a time. But after repeating the training for a while he was able to break a lot more bones than before. He had grown more tolerant of pain.