You believe his reign begins at the 2nd coming? That's when his reign in merciful patience over the unsaved ends.
Scripture disagrees:
The arrival of Christ for the second time accomplishes many things including the vials of wrath and destroying the army of the beast at Armageddon as well as resulting in the beast and false prophet being cast into the LOF. There is one more thing mentioned during the second coming that many do not notice which is
the future rule over the nations which proves there are unsaved mortals that are set aside for being ruled over by the rod of iron:
Rev 19:15 And out of his mouth goeth a sharp sword, that with it he should
smite (Aorist tense verb with PRESENT tense meaning) the nations: and he
shall rule (FUTURE tense verb) them with a rod of iron: and he
treadeth (PRESENT tense verb) the winepress of the fierceness and wrath of Almighty God.
Here rule/poimaino is in the
FUTURE tense meaning it will happen at some point AFTER the second coming and battle of Armageddon while treadeth/pateo is written in the
PRESENT tense meaning it is happening during this second coming. The treading and smiting are happening at Armageddon but not the ruling which proves mortals will be alive after Armageddon is over. This proves the Premill position because indeed
there is a future rule of people who were not slain during the second coming that Christ and his saints will rule over.
A second witness to this:
Rev 2:25 But that which ye have already hold fast
till I come.
That is the second coming. Everything we read of next comes after the second coming:
Rev 2:26 And he that overcometh, and keepeth my works
unto the end, to him will
I give power over the nations:
After "the end" comes, there is given power over the nations to those that are overcomers which naturally includes those who "are alive and remain" at the second coming. They will be given power over the mortal unsaved nations after Christ has returned
not before it.
Rev 2:27 And he
shall rule (FUTURE tense verb) them with a rod of iron; as the vessels of a potter shall they be broken to shivers: even as I received of my Father.
After the second coming and after "the end" will the overcomers be given power over the nations, ruling them with a rod of iron. That proves the rod of iron rule over the nations for a thousand years does not even start until Christ has returned and has given overcomers this power to rule over the nations.
It is impossible to understand what happens at the second coming and what happens AFTER the second coming properly without understanding the verb tenses involved.
Since scripture does not contradict itself,
there are no scriptures which state all mortals are slain at the second coming leaving none to be ruled over.