This would be a nature-grown set of ancient ruins. I have made a few enemies for the area.
First up, we got basic guard enemies: the Logon Guard.:

These spear-toting Logons serve as guards in the Ruins themselves. Here are their stats:
Name: Logon Guard
HP: 210
Defense: 123
Power: 375
EXP: 275
Weight: 355 lbs
Eliapedia Entry: Logons at the Metztli Ruins wore armor from times long forgotten and serve as guards for the goddess Moonchyllus. They stand firm against Xantis' forces, using their spears to fend off any agent or police officer that comes their way. So proficient are they with their spears that Logon guards pierced the engines of military vehicles when they fought. Unlike their fresh counterparts in Red Leaf Hills, Logon guards from Metztli Ruins are less aggressive and more straightforward when combating opponents. Xantis' first notable loss prior to your appearance in Eliatopia was against Logon guards that managed to drive him away from the ruins. Uncertain as to how strong Xantis will be when he makes his return, Logons continued to fight invaders that wrongly set foot in the Ruins.
Drops:
Twig: $27; 10%; 2.7
Apple: $67; 10%; 6.7
Wood Buckler: $4517; 2%; 90.34
Wood Knee Pads: $20083; 0.4%; 80.332
Log Helmet: $35578; 0.2%; 71.156
Wood Armor: $35578; 0.2%; 71.156
Tribal Spear: $41523; 0.2%; 83.046
Scutum Shield: $45457; 0.2%; 90.914
Rusted Bronze Helmet: $57642; 0.2%; 115.284
Stage 3 Sharpening Stone: $3; ???
Stage 4 Sharpening Stone: $4; ???
Stage 3 Fire Rune: $3; ???
Total Loot Value: 611.628

He has three attacks: a normal physical attack, a fire spell, and an AOE lightning spell that does electrical damage. Yep. Now, for its stats.
Name: Druid
HP: 2000
Defense: 96
Power: 350
Fire Power: 200
Heal: 50 HP/second
EXP: 511
Weight: 6000 lbs
Eliapedia Entry: Logons capable of wielding magic swiftly metamorphose into Druids, who are significantly more powerful than the average Logon. Using their advanced magical knowledge and affinity with Moonchyllus, Druids can cast powerful Fire and Thunder spells. When a druid needs to rest, it roots itself into the ground, healing whatever damage the Druid took. A Druid is capable of wielding four Forsaken Hammers in its four arms, although it prefers to use two Wood Gem Staves. Druids are capable of feats of intelligence similar to that of humans and are even capable of speech. Weirdly enough, a Druid wouldn't back down on a challenge once a challenger approaches it. A Druid's fire is capable of burning an entire Gal Roach alive, making it tough to approach a Druid swords-a-blazin'.
Drop List:
Apple: $67; 20%; 13.4
Hawthorn Wand: $125; 5%; 6.25
Club: $358; 5%; 17.9
Cleric's Cross: $5600; 1%; 56
Nature Bow: $9676; 1%; 96.76
Wood Knee Pads: $20083; 0.2%; 40.166
Wood Gem Wand: $27000; 0.2%; 54
Log Helmet: $35578; 0.1%; 35.578
Wood Armor: $35578; 0.1%; 35.578
Wood Gem Staff: $55654; 1%; 556.54
Ground Armor: $357869; 0.05%; 178.9345
Stage 2 Hardening Stone: $2; ???
Stage 3 Fire Rune: $3; ???
Stage 3 Electric Rune: $3; ???
Stage 4 Fire Rune: $4; ???
Stage 4 Electric Rune: $4; ???
Total Loot Value: 1091.1065
Monster #3 shall be the Montezuma!

Yep. We got a Montezuma: a stone golem that will slam down into the ground, causing a shockwave that deals less damage the further away you are. That being said...
Name: Montezuma
HP: 3200
Defense: 180
Power: 400
EXP: 822
Weight: 40000 lbs
Eliapedia Entry: Claystones from the Nature Factory are rushed counterparts of the Montezuma. While the Claystone only comes as crude heads, the Montezuma are marvelous hand-carved golems fueled by the magic of Moonchyllus herself, as soon by the Moonchyllus insignia on the back of their heads and on their chests. Their mighty slams cause shockwaves that deal major damage to foes regardless of whether they are near or not. Montezumas often ate the sacrifices of the civilization that once resided in the Metztli Ruins, as Montezumas were believed to bring about a bountiful harvest. The sacrificial ceremonies done in honor of the Montezumas are quite frankly too gruesome to put in this game. A Montezuma is capable of smashing a tank, which allows them to help protect the Metztli Ruins from Xantis' efforts in conquest.
Drops
Pizza: $472; 10%; 47.2
Sledgehammer: $1537; 2%; 30.74
Dreamcatcher: $27512; 1%; 275.12
Tribal Spear: $41523; 0.2%; 83.046
Ground Boots: $45672; 0.25%; 114.18
Peacock Feathers: $142852; 0.1%; 142.852
Ground Helmet: $357869; 0.05%; 178.9345
Ground Armor: $357869; 0.05%; 178.9345
Ground Legs: $357869; 0.05%; 178.9345
Back Igneous Rock: $639358; 0.02%; 127.8716
Combustion Rock: $1467663; 0.02%; 293.5326
Stage 3 Hardening Stone: $3; ???
Stage 4 Hardening Stone: $4; ???
Total Loot Value: 1651.3457
After that, we got the 4th mob: the Quetzalcoatl:

The Quetzalcoatl is based on the primary god of Mesoamerican mythology, Quetzalcoatl. As such, this guy fires off solar beams and tornadoes. Hoo boy!
Name: Quetzalcoatl
HP: 4000
Defense: 120
Power: 450
Fire Power: 280
EXP: 798
Weight: 1050 lbs
Eliapedia Entry: The Quetzalcoatl is a giant feathered serpent once worshipped by the people of the Metztli Ruins. Quetzalcoatls are capable of using the power of the sun to fire off powerful bursts of energy. They have keen eyes that allows them to see threats from miles away. Quetzalcoatls typically eat Scorpees, Blizzers, and Proteums, though it is important to note that Proteums in Eliatopia are only about twelve feet in length and are more sharklike than Helmetopian Proteums. Like Earth's anacondas, Quetzalcoatls typically constrict their prey, choking them to death before eating them. Their fanged maws, however, lets them bite bits of prey one by one. It is said that Moonchyllus made the Quetzalcoatl feathery for a reptile in order to make riding on them more comfortable. Natives often slept on Quetzalcoatls after using specialized saddles that would prevent them from falling off the serpentine beasts.
Drops:
Green Soda: $247; 20%; 49.4
Cobra Boots: $7532; 1%; 75.32
Reptile Wand: $9261; 1%; 92.61
Feather Mantle: $9677; 1%; 96.77
Cobra Tail: $23394; 0.5%; 116.97
Cobra Hood: $54486; 0.2%; 108.972
Cobra Armor: $54486; 0.2%; 108.972
Cobra Legs: $54486; 0.2%; 108.972
Jungle Shoes: $62001; 0.2%; 124.002
Cobra Whip: $63787; 0.2%; 127.574
Peacock Feathers: $142852; 0.1%; 142.852
Jungle Bow: $477030; 0.02%; 95.406
Jungle Helmet: $503552; 0.02%; 100.7104
Jungle Armor: $503552; 0.02%; 100.7104
Jungle Legs: $503552; 0.02%; 100.7104
Stage 3 Fire Rune: $3; ???
Stage 4 Fire Rune: $4; ???
Stage 1 Ice Rune: $1; ???
Stage 2 Ice Rune: $2; ???
Total Loot Value: 1549.9512
Okay, now that that's done, now it's time to introduce the boss...
Moonchyllus

Yes, she's back! While plans to make her a partner for Cionic Organism are currently on limbo (just like the Alion City casino), I've made this as a backup option. The lore of her is basically well-known, but long story short, Moonchyllus is Mother Nature and serves as the antithesis to Xantis.
Here is a picture of her battle in action:

As for her stats, well...:
Name: Moonchyllus
HP: 28000
Defense: 144
Power: 420
EXP: 6878
Weight: 1050 lbs
Eliapedia Entry: Alright, you got me. I should tell you about myself now that you've beaten me. I am the one who created the planet Eliatopia and all life within. The Logons, Stalagmites, Great Frogs, and Blizzers you've seen throughout your journey served as my eyes on the planet. If you've seen them acting aggressively towards you, it's the result of my anger towards Xantis. In the countless millennia of my existence, Xantis is perhaps the greatest threat to Eliatopia. As a result, I had to take action against him, first by having my creations fight against Xantis' troops and then commandeering Cionic Organism, who you may have known as Alex. I will say this, human, your fight against Xantis isn't over yet. You may have taken on his factories, but you have yet to handle Xantis' military bases. Only when you take them out will you have a chance at beating Xantis once and for all.
Drops:
Cleric's Cross: $5600; 25%; 1400
(Other drops whose drop rates I'm uncertain of are as follows)
Moonlight Helmet
Moonlight Armor
Moonlight Legs
Moonlight Boots
Moonlight Wand
Moonlight Staff
Priest Sandals
Priest Hat
Priest Robe
Priest Pants
Priest Wand
Priest Staff
Ground Helmet
Ground Armor
Ground Legs
Ground Boots
Jungle Bow
Tribal Bamboo Bow
Crescent Wand
Crescent Staff
Stage 4 Fire Rune
Stage 4 Ice Rune
Stage 4 Electric Rune
Stage 4 Poison Rune
Stage 5 Electric Rune
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Whew! Well, there's that.