Don't know if the First Beast is killing anyone in respect of the mark.
The Second Beast is the one who implements the mark and has people executed.
Also, who is the Harlot?
The first beast is the one who governs the promised land.In the book of Daniel it is described as being little but stout .
Compare
Revelation 13
5 And there was given unto him a mouth speaking great things and blasphemies; and
power was given unto him to continue forty and two months.
6 And he opened his mouth in blasphemy against God, to blaspheme his name, and his tabernacle, and them that dwell in heaven.
7 And it was given unto him to make war with the saints, and to overcome them: and power was given him over all kindreds, and tongues, and nations.
Daniel 7
24 And the ten horns out of this kingdom are ten kings that shall arise: and another shall rise after them; and he shall be diverse from the first, and he shall subdue three kings.
25 And he shall speak great words against the most High, and shall wear out the saints of the most High, and think to change times and laws: and they shall be given into his hand until a time and times and the dividing of time.
26 But the judgment shall sit, and they shall take away his dominion, to consume and to destroy it unto the end.
27 And the kingdom and dominion, and the greatness of the kingdom under the whole heaven, shall be given to the people of the saints of the most High, whose kingdom is an everlasting kingdom, and all dominions shall serve and obey him.
After the beast is destroyed,the saints in Israel recieve the land that was promised to them thousands of years ago.