'One' in the Bible

It is right for us to give praise to God at all times for you, brothers, because of the great increase of your faith, and the wealth of your love for one another;

For the secret of evil is even now at work: but there is one who is keeping back the evil till he is taken out of the way.

And then will come the revelation of that evil one, whom the Lord Jesus will put to death with the breath of his mouth, and give to destruction by the revelation of his coming;

Even the one whose coming is marked by the working of Satan, with all power and signs and false wonders,