"Blood Protector" is an archetype of mostly WATER monsters mostly used Composition Monsters. "Blood Protector Composition Dragon" is also part of the archetype, and as well as it's counterpart "Blood Protector Utopia Dragon". They usually relied on defensive effects to keep them alive long enough to Composition Summon, which is also easier since the archetype has Synchro Monsters as well.
"Blood Protector" monsters usually relied on defensively, and in some cases involved regaining LP through their effect. As most of them are WATER monsters, cards such as "" is useful due to the fact that most of them don't have more than 1500 ATK.