The Legacy of Kain Series: Blood Omen 2 (2002)
Chronologically, Blood Omen 2 is the most direct sequel to 1996's Blood Omen: Legacy of Kain, continuing the story of a younger Kain. Its development period overlapped with Soul Reaver 2's, and it again had Kain as the playable character.
Two centuries after the events of Blood Omen, Kain had built a vampire army, and led them south to conquer Nosgoth. However, outside of Meridian - Nosgoth's capital city - Kain's army was defeated by another. The Sarafan Lord, a mysterious and powerful warlord, had revived the long-defunct Sarafan order to battle the vampires. Kain was beaten in combat by the Sarafan Lord and left for dead.
Kain survived - just barely. Another two centuries passed before he awoke from his injury-induced coma, but although he had kept his life, he had lost the Soul Reaver. With the help of the vampires who had protected him during his recovery, Kain set about reclaiming the sword, continuing his ascent to power, and taking his revenge on the Sarafan Lord. Along the way, he would learn about the Hylden - the race cryptically mentioned by Kain in Soul Reaver 2 - and fight traitorous vampires who had sided with the Sarafan for personal gain.
Amongst Legacy of Kain fans, Blood Omen 2 is generally the least popular game in the series. Some long-term followers thought it suffered in trying to appeal more to 'mainstream' game players. There was a mixed reaction to the character of Umah, and the way established characters - including Kain - were portrayed. Also, it was initially unclear if Blood Omen 2 took Soul Reaver 2's history-defying climax into consideration (it did), and the game prompted the most frequently asked question ever: how was Vorador alive following his earlier execution? We still don't know the answer to that one.
As a result, Blood Omen 2 is sometimes viewed as a spinoff of the Legacy of Kain story rather than a true sequel, however its events are still considered canon. Admittedly, Blood Omen 2 has its flaws, but for many people, it remains an enjoyable addition to the series.