Trapped Under Ocean

After discovering the healing effect of the cursed blood, Jacob used magic gem after magic gem, and his body began to go back to its original state. However, this process was quite long and costly. 

To return to his peak, Jacob used over 5000 advanced unique rank magic gems, which were enough to power an advanced unique rank flying ship for about a month at full capacity. 

An advanced unique rank magic gem has mana equal to 100 intermediate unique rank magic gems and far more condensed and pure quality. To make an advanced unique rank magic gem, one needed 1000 magic cores of at least tier-7 unique rank, so one can only imagine how precious an advanced rank magic gem was. 

Jacob only got around five hundred thousand magic gems from Captain Free Sword's entire crew, and this was the accumulation of hundreds of years of plundering. After his voyage to the unique plains, he had already spent more than a hundred thousand of them.