[Guest]

I am the center of gravity, hold a capital situation in Vienna, and as I am foremost in every victory, am allowed by all to be invaluable. Though I am invisible, I am clearly seen in the midst of a river. I could name three who are in love with me and have three associates in vice. It is vain that you seek me for I have long been in heaven yet even now lie embalmed in the grave. What am I?

[araver]

letter v

I've seen the pattern after the bold words:

I am the center of gravity, hold a capital situation in Vienna, and as I am foremost in every victory, am allowed by all to be invaluable. Though I am invisible, I am clearly seen in the midst of a river. I could name three who are in love with me and have three associates in vice. It is vain that you seek me for I have long been in heaven yet even now lie embalmed in the grave. What am I?

[Guest]

Good job, araver! Beat me to it! @jake- it may be a commonly found riddle, but its very well written. Good job!

[Akriti]

letter v I've seen the pattern after the bold words:I am the center of gravity, hold a capital situation in Vienna, and as I am foremost in every victory, am allowed by all to be invaluable. Though I am invisible, I am clearly seen in the midst of a river. I could name three who are in love with me and have three associates in vice. It is vain that you seek me for I have long been in heaven yet even now lie embalmed in the grave. What am I?

That was quite easy.