If the Song aren't in, I feel like this would be a cool generic unit unlocked with alchemy. If that makes too many units for the Medieval Era though, then maybe through the event system as a special unlock, like "you were the first to research alchemy" or "you have alchemy and also x amount of melee units" or something. Or, as an alternative to the Halberdier when upgrading melee units that has limited range but isn't quite a gunner.
As I understand it, fire lances were, with a few exceptions, mostly limited to China and were obsoleted by more advanced gunpowder weapons like rockets by the time they were spread out of the region, but it always feels a little weird that there's no intermediate weapon between swordsmen and guns to me. Ming Rocket Cart sort of addresses this, and obviously if the Song were included fire lances would be an excellent candidate for an EU, but if the Song aren't in I think generic fire lances/ early rockets would be cool to see in the game somehow.
Going to try to address everybody's posts here without filling another page with 'Quotes':
The "Fire Lance" is first described in 950 CE, but not specifically mentioned in use until about 1130 CE: at about the same time the first "hand cannon" firing projectiles is also described (1128 CE at Dazu, China)
BUT in 1280 CE (barely 150 years later) Italian city states are described as including "hand cannon" among their armies.
That would make the Hand Cannon a good candidate for a Late Medieval Ranged unit, except they really don't seem to have had any major effect on the battlefield, either in Europe or China - being shorter ranged and less accurate than either bows or crossbows.
The
Huo Long Jing, or "Fire Dragon Manual" of 1395 CE describes all the gunpowder-derived weaponry developed in China since about 1280 CE, but, unfortunately, doesn't give us more accurate dates than "since 1355 (roughly)" for the use of Hand Cannon, Wheeled Cannon, bombs, grenades, land nd naval mines, fire arrows, etc.
But the definite first use of a Bombard in Europe (France, to be specific) was 1375 CE when one was used to put a hole in a city wall, and just 5 years later they are recorded being mounted on Venetian Galleys and killing a Genoese admiral with "artillery fire" at the Battle of Chiogga.
In 1470 CE a shoulder stock as added to the
Hackbus, a defensive gunpowder weapon mounted on walls, to make it the
Arquebus, with a matchlock trigger mechanism (1472 CE) the first gunpowder bullet-thrower that could be aimed from the shoulder and fired by one man.
About 20 years later (1 -2 Game Turns?) they are combined with pikes (and halberds and swordsmen) by fhe Spanish into
Colunelas of 1000 men each, the first "pike and shot" units anywhere.
In 1475 CE occurs the last known use of a trebuchet or catapult in a European siege - 100 years after the first Bombard, they had made all the older Siege weaponry Obsolete. (55 years later 3 Colunelas are combined into the more-famous
Tercio, which becomes the standard Tactical pike & shot unit in the Spanish Army for the next 150 years)
To summarize:
The
Hand Cannon of the late Medieval (1130 - 1280 CE) is an appropriate general ranged unit for that period, but is not really a significant improvement over existing ranged weapons, so just a little pointless.
The numerous Chinese defensive and siege weaponry, like naval and land mines and gunpowder grenades and bombs, I submit are better indicated as improvements in Defensive Strength of fortifications from about 1200 CE on.
The
Bombard of about 1375 CE (and made of cast iron from about 1410 CE on) is the first Decisive gunpowder weapon: it literally made all previous stone defensive walls Instantly Obsolete, which included not only all the defended cities in Europe, but also all the Castles cluttering up the countryside, which shortly thereafter became either Chateaus or Manor Houses or picturesque Ruins (cue the Romantic Movement of the early 19th century, which 'repurposed' many of them)
About 100 years Later comes the true Hand Gun, the
Arquebus. Note that this sequence is the opposite of every Civ game so far, which always introduces the 'Musketman' earlier in the Tech Tree - wrongly.
Now, in
Humankind (at least according to what I could glean out of the Tech Tree in the Victor Open Dev just concluded):
In the Medieval Era they introduce the Knight, Pikeman, Crossbowman (no surprises there) but also the Great Swordsman (Civ VI's new Man-at-Arms, basically)
In the Early Modern (Renaissance) Era they have the Halberdier - an Upgraded Pikeman, and the Arquebusier and 'Mortar' - the Mortar is actually a Bombard, based on both the artwork and the narrative that goes with it: "... These early cannons fire enormous solid shot to break down city walls". Unfortunately, it comes a full tier of Tech after the Arquebusier, thus perpetuating the mistake made in Civ VI, and the unit is completely mislabeled.
They do not have any new cavalry units in the Early Modern Era, thus missing the Gens d'armes armored knights that tried replacing the lance with pistols. Since this was a huge step back in cavalry effectiveness, there is a reason both Civ and Humankind pass them by!