Triage X

Tired? Stressed? You will feel better sitting on the couch watching fanservice (the source of all problems). Storylines play no important role in these two worlds where sexual attraction and pleasure conquers all. ‘Highschool of the Dead’ puts you in a world of zombie filled with stench of death where hope is the furthest thing from one’s mind. In the depths of this crisis, a group of gorgeous females charms the city with both their look and appealing physiques. It is almost impossible to miss out on a potentially hot scene wherever you are. There is nothing more satisfying than seeing beautiful woman taking out zombies one after another and paradise is destined for the guys in the group. ‘Triage X’ set its sight in a city filled with corruption and hidden in the shadows, lays a group of dark knights sworn to purge the city of this disease. Aside from the killing, it does not hurt to have woman with lustful bodies taking over the screen (fanservice style) regardless of their individual importance. Torture is used as an element to add another level of pleasure in the already sweet gratification. That alone is enough to divert a person’s attention away from the great songs and character development in the series.  read more 

Both animes have to do with the main protagonists fighting against criminal organizations who have ties with drugs, prostitution and other criminal activities. Also both animes have their share of blood and some ecchi moments. 

Both have boobs, overpowered characters, boobs, friendship themes, boobs, yuri bits, boobs, ass, boobs, action, and boobs. Did I mention the boobs? 

Both are a group of people in an underground (vigilante-like) organisation who want to protect their city from evil, the difference is that Release the Spice has a more "cute girls" concept and Triage X has more fanservice. 

both are simple guilty pleasure shows with a high amount of sex and violence 

Both involves bikes that look great both have somewhat of a plot nothing great still more plot than Michael bay stuff. But the anime is more like sit back and watch it nothing insanely complex but a fun watch. 

- Both MC are cynical, has a mysterious difficult past and are exceptionally skilled shooters, therefore they remind of each other - Both series has a school setting with a slight of ecchi though - While the plot of GnK is a drama/psychological-focused plot, Triage X goes by action/adventure. Altough the story of them differ from each other 

Both of these anime focus on gunplay with characters that are rough and have been through tough times in their pasts. Just like in Triage X, you'll find violence and plenty of women that you wouldn't want to mess with. Corruption is found around every corner in both series. 

- group of people who kill people deemed unfit to live - people are being judged and are said to be a certain color - psychological (when is it ok to kill a person?) 

They focus on group of assassins who have been through tragedy. The group isn't part of the goverement/police. They kill people who they deem to be corrupt and harming society. They both include a harem and ecchi.  

Main Similarity: •OPPAI! (Must I say more?) (Some other similarities if you're not convinced: •The main characters have a somewhat similar personality. They are both very strong as well. •Most of the female cast has a crush on the main character. •On top of boobs, there are also action scenes (like thats the reason why we watch these).