Many participants use a drug called "Rein," which temporarily boosts their strength significantly and gives them an advantage in battle; however, Rein has many side effects, is extremely addictive, and the withdrawal is unbearably unpleasant and can even be fatal. Il Re is involved in the distribution of Rein, which leads to him having a high level of wealth. If they defeat Il Re, they assume his position in distributing Rein and become incredibly wealthy, which is the primary motivation for many of the fighters who join Igura.