Age of Mythology: Retold

This can be more easily done on Campaign Mission 4: A Fine Plan on Story Mode Difficulty.

To begin, gather your forces and start wiping out all the enemy storehouses abut put emphasis on the storehouse at the two gold mine veins nearest to Troy's base (more on that later). It also helps to quickly clear out the enemy base to the west of your camp. You should have more than enough to clear all the storehouses and this base with no concerns.

Next, you should boom your economy in order to age up. Choose Dionysus as his Temple Upgrade (Dionysia) gives all your units extra hitpoints including Colossi. Have some villagers build a second town center in the western camp and upgrade to fortified town centre so you can get plenty of pop space without the need to spam houses. You will, of course, need to pick Hephaestus for your Mythic Age Minor God in order to build Colossi but you can get this with your starting Colossus anyway, make sure to get both the Dionysia upgrade and the two upgrades for the Colossus in order to maximise their hitpoints.

Next, task your Colossus towards the two gold mines form earlier and attack a few caravans. Have him kill a few troops that troy will send out then task him to 'eat' at the untouched Gold Mine that should still be showing as 6000 gold in all. Yu can use this as your reference. leave at least one Hippus alive that will continue to attack the Colossus as he regains health from the gold mine. Troy will send out a few more Hippus but no more than four un-upgraded horsemen on the easier difficulties.

Now, with the four units constantly attacking they will do more damage than the Colossus can heal from the gold mine. What I did was waited until they got him down to about half health (900 or so) and casted the Bronze Power to reduce the damage taken and increase the healing speed. provided that the gold mine was at 6000 gold at the start of the eating process you can safely assume you will be getting this achievement as soon as it gets to about less than 1000 gold. It would be an idea to have a second Colossus ready, should your first one die but I personally didn't need to build one.

Colossi, fully upgraded, have about 1800 HP. I got this with four of them. I carefully let them fight enemies, until they had about 300ish HP left each. Then I withdrew them to two cold mines I had kept untouched for that reason to feed on. It requires less micromanagment than trees.

You can do this in any scenario you can worship Hephaistos in (he can be worshipped by any major Greek God), or skirmish, but I got it in the 19th Scenario, because you them for free and there is a chokepoint, through which I could precisely control how damaged the Colossie became, before needing to withdraw them.

Colossus can be made in Mythic age when worshiping Hephaestus.

Simply select the colossus and right click in a tree or a gold mine and it’ll start healing.