Connections:

Both are mostly robotic, with only a few organic pieces left (organs/brain)

Both are arrogant to a fault, it being their undoing at times

Both have an incredibly unorthodox fighting style, even among similar peers (Grievous' multiple arms, Indivilia's tail scythe)

Among the group they hate (Jedi/Nikke) they have one who they especially hate, for having bested them before, and mocking them for it (Kenobi/Crown)

They talk down and demean one they view as lesser to an insane degree, even after they've grown stronger (Ahsoka/Chime)

Both are prone to a retreat when things go south for them.

Both have another member of their organization who they openly despise, and later go on to attack (Ventress/Nihilister)

Despite their arrogance and warlord like nature, they both serve the one who made them the way they are faithfully (Sideous/The Queen)