Forgot who said it, but Lothric is where all the lands of the Lords are converging. Apparently, that means the whole geography is being sucked in towards Lothric, hence the messed up geography.
It's the introductory cutscene. "Converge" can also mean "come together" in a passive rather than an active sense, but she also describes the domains of the Lords of Cinder as "transitory lands." So, you might be right.
Silas:
Ah, wacky invaders.
You may, then, appreciate
Friendship Chest.
To clarify what you're seeing:
[spoiler]Friendship Chest's headpiece, the "Chest," is a "helmet" that greatly increases drop rate for valuable items-- at the cost of continuous health drain. As a result, Friendship Chest is permanently running on a timer, and has only so many healing resources.
And-- and here's where this gets particularly special-- he has very low to absolutely zero straightforward offensive capability and minimal defense. He's got a broken sword, a Miracle-casting talisman that he uses for healing spells and a nonlethal force blast, and a Pyromancy flame (usually freaking lethal) that he only uses to cast a healing spell
that heals everyone, friend or foe. Hence, he's a "benevolent" invader who shows up and casts healing spells at your party.
... and then, once you've accepted his presence, might or might not force-blast you or your comrades off a ledge into a pit of lava.
If you don't accept his presence, he knows the environment well enough to use it to kill you oh so very dead. (That last kill, where he keeps someone stuck in that bug-eyed lizard's gas cloud, is particularly wicked: Curse is a status effect that causes instant death if it takes, but keeping someone who knows what they're doing stuck there long enough for that to happen is a definite skill-shot.)
But he's nice! Really![/spoiler]