Understanding the particle や in the phrase "今や"

(Moved from Insertion of "y" sound between vowels since it appeared to be unrelated.)

In the following quote:

私の世界へようこそ。 今やこの世界をコントロールできる唯一の人間だ。

What is the function of the particle や here? I see a definition for 今や in edict:

now (esp. in contrast to the past); now at last; at present; right now

I don't understand how や figures into this, though. I would have expected 今は. Is there any way to understand the function of や here, or should I memorize 今や as a set phrase?

Answer

Goo lists this や as being a 強意の間投助詞, i.e. an interjectory particle used for emphasis.

That would be definition 4-2 here, where it also mentions またもや

I don't think this や is really productive anymore, so I would memorize 今や as a word/an expression by itself.