If you're looking for manga similar to MARS RED, you might like these titles.
The year is 2017. Global climate change has devastated the Earth. This is now a cyberworld in constant dread of war. The state of Denmark has grown prosperous and defended itself successfully against neighbouring states. But could it be that its greatest threat comes not from without, but from within the state itself? It is in this cyberworld that we find the young Hamlet. His grief over his father's recent death turns to something far darker when the ghost of his father appears to him. Hamlet is very soon to discover that something is rotten in the state of Denmark...
Sophie, a boy with vampire and human blood, is transferred from an orphanage to an institution called Clan. The school houses vampire boys who have reached their Cocoon period, or puberty in human terms. Sophie has a fateful encounter with a boy while being coldly greeted by the vampires around him. A manga adaptation of the origin story of playwright Kenichi Suemitsu’s popular series!
The Van Helsing Church Order is bent on destroying all supernatural creatures, as well as anyone else who gets in their way. However, a certain silver-haired man and red-haired vampire are not waiting for the Church to come to them! During their latest attack on a Van Helsing "cleansing" squad, they inadvertently save the life of a human being..
In the not so distant future, Earth is invaded by aliens. The United Nations instates a draft, and all humans on Earth are eligible to become soldiers. Kurando Nieno is a rather scrawny high school student, scoring the lowest scores possible on the preliminary draft physical. During an air raid from the aforementioned aliens, a rather irritable black haired girl crash lands in front of Nieno and attempts to drink his blood. The United Nations air force and Eliza the vampire have selected Nieno as Eliza's delicious new food source!