Fetching details from the dictionary...
this; this one
this person
now; this point (in time)
used to stress the subject of a sentence
惟こそが真実だと思う。
I believe this is the truth.
惟は大事な資料である。
This is an important document.
惟を知った上で判断してほしいと思う。
I want you to make a judgment knowing this.