The user can unify the complementary forces of yin and yang of all beings and forces by unifying the fused forces or entities that can embody the combined essences of differing forces (day and night, love and hate, light and darkness, male and female, etc.).
Hōgyoku (Bleach); can unify the essence of Hollows and Shinigami
Rebellion (Devil May Cry series)
The Tiger Talisman (Jackie Chan Adventures)
χ-blade (Kingdom Hearts series)
Guy Gardner (DC Comics) wielding Green and Red Power Rings.
The Visored (Bleach) use Hollowfication to fuse their Shinigami and Hollow powers, vastly enhancing their abilities.
As a Full Hollow, Ichigo Kurosaki (Bleach) had his Shinigami and Hollow powers completely merged into a single form,..
...tremendously enhancing his spiritual powers and abilities...
...and after his training by the Royal Guard, he achieved a fully stabilize unification of his spiritual powers as a Hollow, Quincy and Shinigami, granting him transcendent powers to match the Soul King.
V (Devil May Cry 5) impales Urizen, merging the human and demon halves...
...back into their completed self, Vergil.
Dante (Devil May Cry series) uses the Rebellion to fully unify his human and demon halves...
Jacen Solo (Star Wars Legends) unifies the light and dark sides of the Force in a state of perfect balance, achieving Oneness with the Force.
The Tiger Talisman (Jackie Chan Adventures) splits the user's Yin (light side) and Yang (dark side) halves into two separate beings and can also unify them back together.
As the carrier of the Tiger Talisman power, Sasha (Jackie Chan Adventures) can separate her Yin and Yang halves, and unify them again.
The χ-blade (Kingdom Hearts series) is created by the union of seven lights and thirteen darknesses.
The Witchblade (Witchblade/Top Cow) was born to the opposing forces of the Darkness and the Angelus to serve as a balance keeper between them; as a result, it possesses traits from both of its parents.
Lara Croft (Top Cow) using the Weave, a combination of the Angelus and the Darkness.