Miles in ultima acie stat.

Because miles is the subject of the sentence, so it is in the nominative singular.

• miles = the soldier as the one doing the action
• militem would be accusative singular, usually used for a direct object
• militis would be genitive singular, meaning of the soldier

In Miles in ultima acie stat, the soldier is the one who stands, so Latin uses the nominative: miles.

Acie is ablative singular.

It is used because the preposition in can take the ablative when it means in / on / at a place.

So:

• in + ablative = location: in, on, at
• in + accusative = motion into: into, onto

Here the sentence means the soldier is standing in a position, not moving into it, so Latin uses the ablative:

• in ultima acie = in the last line / at the rear battle line

Because the adjective must agree with the noun it describes.

Here:

• acies is a feminine noun
• in this sentence it is ablative singular
• so the adjective ultimus, -a, -um must also be feminine ablative singular

That gives:

• ultima acie

So both words match in:

• gender: feminine
• number: singular
• case: ablative

In this sentence, acies means something like battle line, line of troops, or rank.

It can have several related meanings in Latin depending on context, including:

• sharp edge
• line of battle
• front / battle formation

In in ultima acie, it refers to a military formation, so the idea is in the last line or in the rear rank.

Latin word order is much more flexible than English word order because the endings show the grammatical relationships.

English depends heavily on position:

• The soldier stands in the last line

Latin can move words around more freely because:

• miles is clearly nominative
• acie is clearly ablative after in
• stat is the verb

So Miles in ultima acie stat is a perfectly normal Latin order. It puts the subject first and the verb at the end, which is very common in Latin.

Other orders could also be possible, for example:

• In ultima acie miles stat
• Stat miles in ultima acie

The basic meaning would stay the same, though the emphasis might shift.

Latin has no definite article and no indefinite article.

So Latin does not normally have separate words for:

• the
• a / an

That means:

• miles can mean the soldier or a soldier
• the exact translation depends on context

So even though English says the soldier, Latin just says miles.

Stat literally means stands, from the verb sto, stare.

But like English stand, it can also mean:

• is standing
• stands positioned
• remains
• is stationed

In this sentence, stat probably means not just that the soldier is physically upright, but that he is posted or stands positioned in the rear line.

So stat is simple, but it can carry a slightly broader sense depending on context.

Yes. Ultimus can mean:

• last
• final
• furthest
• outermost
• rearmost

In a military context, ultima acies usually means the last line or rear line of the formation.

So ultima is translated as last here because that fits the military setting best.

It is a fifth-declension noun, not a third-declension noun.

Its dictionary form is:

• acies, aciei — battle line, edge, etc.

Some common forms are:

• nominative singular: acies
• genitive singular: aciei
• accusative singular: aciem
• ablative singular: acie

So acie in this sentence is the expected ablative singular of a fifth-declension noun.

Not in this sentence.

If Latin wanted to say into the last line, it would usually use in with the accusative, not the ablative.

Compare:

• in ultima acie = in / at the last line → location
• in ultimam aciem = into the last line → motion toward

Because the sentence has acie in the ablative, the meaning is location, not movement.

You can tell because:

1. ultima agrees with acie in gender, number, and case
2. the preposition in governs the whole phrase
3. semantically, ultima acie makes sense as the last battle line

So the structure is:

• Miles = subject
• in ultima acie = prepositional phrase showing location
• stat = verb

That is a very common Latin sentence pattern.