Cared for his younger siblings, Cobolda, Denus, and even Drop/Salamandes.
Cared for his friends and fellow demons Loki and Vypra, but was at odd with Impus/Olympius due to them competing for Bansheera's favor.
Cobolda used Godai to try and revive him but it failed and was not revived until near the finale which costs Denus's life.
Was revived shortly after his death by Loki and Vypra just after Olympius tried to kill them. It did not require a monster's aid or Vypra's sacrifice.
Wasn't aware that Salamandes was his younger brother Drop until the finale when Shou and Nagare informed him of this.
Was aware after his revival that Olympius was previously Impus.
Turns against Grandiene in the finale but was possessed by her and had to be killed.
Turns against Queen Bansheera, but ends up being brainwashed by her and had to be destroyed. Despite this, Diabolico's spirit helps the Lightspeed Rangers to seal her in the end.