Out of the "sea" is an indication of a foreign power. This is the leopard-bear-lion beast as in Daniel. This is an amalgam of the beasts in Daniel, signifying all of the world empires.
Daniel 7 - first beast like a lion (v 4), second like a beat (v 5), third like a leopard (v 6), fourth had ten horns (v 7)Then with the seventh head, it was referring to the Roman Empire which was "as it were slain to death but healed" -- the Roman empire was in turmoil with the death of Nero, but it healed
Rev 13:5 and power was given to him to do two and forty months.
-- 42 months, the duration of the first Jewish-Roman war *66AD to 69 AD* culminating in the total utter destruction of Jerusalem (what we now call ancient Jerusalem is actually Aelia Capitolino, the Roman city built by Hadrian in 130 AD)
Rev 13:11 And I saw another beast coming up out of the earth, and he had two horns, like a lamb,
Coming out of the earth - signifying a local, Judean authority - the Sanhedrin and the High Priest in Jerusalem
The chapter ends with a reference to Nero - the 666, The numeric value of Nero Caesar in Hebrew. The Ethiopic manuscript has the number as 616, the numerical value of Nero's name in Hebrew according to its Latin spelling