The Dragons at the bottom are rather interesting. They are each in the shape of infinity, and also are devouring the tail of the other, which is an altered version of the Ouroboros symbol, again referencing infinity and eternity. The concept of Yin and Yang is also present, as that is a constant in the entirety of the Crest, but here it brings to me an odd thought. In the concept of infinity, everything moves in a constant cycle. Time constantly flip flops between two extremes. In one age, that which is considered Light is good and holy, and in the next, the ideas and symbols associated with the Dark in the prior age are now sacred.
The idea behind this is to keep balance. As an external example, if anyone ever cared to play Final Fantasy III, or know the story to it, you find yourself playing as the Warriors of Light to stop the Cloud of Darkness from engulfing the world. However, you find out many years prior, that Warriors of Darkness were similarly sent to save the world from being swallowed by the Light. Light and Dark are at a constant opposition, yet both produce each other, therefore both need each other to exist.
Going back to Dracula, his entire existence is portrayed as the opposition of God. His extreme hatred for God caused him to seek immortality and grow into a being with power to rival God. As such, Dracula is also eternal, unable to be permanently defeated. Thus the struggle between Dracula and God is an infinite cycle.