Anima Spiritia
Later in the series it is revealed that Basara and the rest of Sound Force (Fire Bomber) are the new "Anima Spiritia", the only force capable of defeating the Protodeviln and their Varauta army. However, Basara regards the real enemy, the alien beings known as the Protodeviln, in the same way he regards everyone else: rather than destroying them, he wants to win them over.
At first his singing appears to hurt the renegade Sivil, a female humanoid Protodeviln in whom he recognises his own free-spiritedness, and when she kisses him she is overwhelmed and driven into a comatose state. He continues to sing for her in an effort to reanimate her, inspiring Gigile, another Protodeviln in temporary human form, to do the same. The two become unlikely allies against the other Protodeviln, and Gigile begins to admire Basara, who through the power of music awakens Gigile's true form. However, Gigile self-destructs to protect Sivil afterwards.
In the end, it is Basara's singing what helps the Protodeviln evolve into a Spiritia self-generating race with no need to steal it from humanoids any more.
Read more about this topic: Basara Nekki