If I'm right, the white on his flag is meant to be transparent as to make it a non-rectangular flag.
It's meant to be a swallowtail flag. The vertical white bit is part of the flag, but not the white triangular section.
As a consequence of this, Mitravarta actually has an official "national mantra": Om Mitrave Namah, the mantra for meditation on and invocation of Mitra. There is a second national mantra, which is the famous Gayatri Mantra, which when simplified, is a prayer to the sun god Savitr.
One question, do you think the mods would allow a Hindu swastika on my flag? I see Athara Magarat has one (reversed one, but a swastika regardless) on theirs.
The mods will pester you initially (and some idiots on the forums) but so long as you provide a reason that distinguishes yours from the nazi version and display it for people to see you'll be fine to keep it.
Just to check: is it allowed if an original language with English translation is given?
Context would be e.g. quotations of existing literary texts in non-English languages; giving the original would allow readers to either read that (if they know the language) or to look for alternative translations to be sure of their meaning.
I realise that such situations may not happen that often here, but just in case :)
The banner and layout of their main overview dispatches are mirror images of each other except for nation names, and Gaya's division factbooks are copies of Hampy's provinces factbook. I've already TGd Gaya on this so please keep the drama down.