bass players should be best friends with their drummers. basically if you are unsure of yourself at first just play root notes to the drum rhythms. listen to the kick drum especially closely... when you start to get more profficient you'll learn to interact with the guitar line... and circle the drum rhythms kind of like being on a big rubber band i suppose.... you ebb and flow with a smooth line which isnt precisely following the drum rhythm... but rather complements and interacts with it. good bass really is a transitional thing supporting the guitar line while rideing tandem with drums to kind of tie everything together through the root notes of the song.
hope i helped some
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Never shall innocent blood be shed. Yet the blood of the wicked shall flow like a river. The three shall spread their blackened wings and be the vengeful striking hammer of God. In nomine Patris, et Filii, et Spiritus Sancti.