Kyoushoku Soukou Guyver (2005), Genocyber Recommendations
They are both dark sci-fi action-packed anime with lots of blood and gore. Both focus on the main protagonist that can transform into a powerful bio humanoid being and can obliterate their enemies with gruesome attacks. They both fight against a secret organization that wants to use their power for evil. The Guyver has a better story and execution, but they are both entertaining to watch. If you like one, you may like the other.