Differences - Anime & Manga

1. While the Blood+ anime is marked with the deaths of important characters like - Riku, Solomon, George; in the Blood+ manga, they are shown to be alive.
2. In the anime, James dies in New York and has plenty of fights with Saya beforehand; James dies on the very first encounter with Saya on Red Shield HQ deck in the manga.
3. Diva forcefully mates with Riku and they have daughters in anime; Riku and Diva never mates on the manga - so no children there.
4. Riku is able to hear Diva's song and is scared of her; the manga shows Riku to want to save Diva from Saya.
5. Mui is Riku's vietnamesse friend and she is shown alive as part-chiropteran in the anime; in the manga Mui is shown as Saya's friend and is killed by Saya after fully turning into a chiropteran.
6. Diva dies in Saya's hands according to the anime; Nathan kills Diva on the manga.
7. Nathan is the strongest and the most mysterious character as per shown in the anime; whereas in the manga he is savagely killed by an enraged Saya after he kills Diva plunging sword into her through Saya.
8. There is no Karl Fei-Ong in the manga, although it has been explained that Carl was renamed Charles by Amshel.
9. There are no schiffs in the manga.
10. Many minor characters like- Glay, Min, Monique, Liza never appear in the manga.
11. The corpse corps on the anime are Moses' clones; in the manga, they are made as Charles' clones.
12. Solomon happened to be Diva's most favorite chevalier in anime; however, Carl was Diva's favorite in the manga.
13. Solomon in the anime loves Saya so much that he died as her chevalier creating a bond beyond blood; in the manga version, he is showed to be more scientist-like, experiment clinging as he tells Van that he'll wait for the next 30 years for Saya to wake up so he can do the mating experiment with her.
14. David never gets drunk in the manga.
15. Diva is showed to hold a grudge against Saya in the anime but on the manga, she is quite obsessed and inclined to her sister.
16. Van Argiano is showed as a much serious character throughout the manga, he is also the one to save Solomon in the end.
17. Saya is depicted as a much stronger fighter than others in the manga while the anime Saya really struggles to keep up even with chevaliers.
18. The scenario in which Haji becomes Saya's chevalier differs greatly between the anime and manga versions. In the anime Haji nearly dies because he climbs down a cliff and falls while trying to pick a flower that Saya wanted for Joel's birthday. In the manga however, it is Diva that nearly kills Haji by impaling his chest out of jealousy.
19. While Saya is shown traveling to many different places in the anime, she only goes to Vietnam and finally New York in the manga. 
20. Rather than the one-year time skip occuring after Saya and Hagi's disappearence, only three months have passed in the manga.
21. David appears to be very resentful of Saya for killing his father and sees her as nothing more than a weapon.
22. When Kai wishes to learn of Saya's history, he threatens Joel Goldschmidt VI with a broken piece of glass.
23. After Riku becomes a chevalier and Saya is fully awakened, she becomes much colder to Kai and those around her, even Hagi.
24. Hagi is portrayed as being jealous and possesive towards Saya.
25. Mao Jahana plays an even lesser role as she is only seen in the first volume.
26. Saya and Riku are seen getting bullied by other students who taunt them for being adopted.
27. Riku gets kidnapped twice.
28. After getting his armed severed by a berserk Saya during the Vietnam War, Charles is demoted from Chevalier status by Amshel and is banned from seeing Diva ever again.
29. The chevaliers never transform into full chiropterans and all seem to possess the ability to change their limbs in the same manner as Solomon.
30. When Red Shield HQ is destroyed, Joel is never injured and therefore not bound to a wheelchair.
31. While Kai is still protective of his sister, he sometimes displays a lecherous attitude towards her.
32. Cinq Flèches is never found out for the experiments they conducted on humans and Van is therefor never arrested.
33. Though they are in the same location, the Metropolitan Opera House is simply reffered to as 'Lincoln Center'.
34. Characters like Okamura and Archer do not appear.
35. Collins makes only one brief appearance in the manga.
36. Julia and Collins never betray Red Shield.
37. Riku's death differs greatly in this adaptation. Here, he is shot by Van while trying to protect Charles.