I don't think it is necessary to add D.
I don't think it is even necessary to add any initials.
There are many cryptocurrencies which don't have any initials in logo and still look great.
BitcoinDark for example doesn't have any letters. Just a cool yin yang and wirl based logo.
I decided to apply Litecoin Letter to refer to Litecoin and then I added a network or Earth's background to point out LitecoinDark's utility for interconnecting between all people around the world and improving the quality of life of all people all around the planet...