There is a jar called Iron Fist Alexander in the NPC of ELDEN RING.

You may think as below:

Why does a jar speak?
What is this guy’s identity?
What’s inside this jar?

In this article, a native Japanese writer explained the lore of Iron Fist Alexander including Japanese backgrounds.

目次 (Contents)

Purpose
Inside the Jar
Fighting with Us
True Identity
Postscript

Purpose

The purpose of Alexander is to be strong.

In fact, Alexander joined the festival of combat to improve himself.

Alexander
I journey to the east, where I intend to further my education in the ways of war.
Beyond these lands lie the scarlet rot-blighted Caelid Wilds.
And upon their southern edge is Redmane Castle, in which a festival of combat is being held.
I’d heard whispers of such festivities before… Doesn’t the notion set your breast aflutter!

Alexander
By the by, do you know for whom this festival is being held? Well, it is none other than General Radahn himself!
To think, I could face a great champion of the Shattering, a demigod in the flesh…
In truth I quiver at the thought, such is his frightful repute. But! The fear simply assures me the ordeal is worth undertaking!
Now, be sure to get a good vantage, my friend. I, Iron Fist Alexander, do hereby vow to unflinchingly brave this ordeal.

Alexander challenged the strongest demigod Radahn as an ordeal, so we can see that he really wants to be strong .

Inside the Jar

By the way, what we must be interested in is the inner contents of Alexander’s jar.

To conclude, the contents inside the Alexander are corpses, which is implied in what Alexander said after fighting with Radahn.

Alexander
…But don’t you think I’ve given up just yet. As luck would have it, there’s a veritable mountain of warriors’ bodies right here.
If I can just squeeze this bunch down inside me, I’ll be a mighty warrior again in no time.
And you know… The bodies found here are exceedingly fine.
Who could expect any less from the very warriors who fought in the Shattering, the greatest of all wars!
Just you wait and see, friend. I’ll grow even stronger! Just you wait, when next we meet! Heh heh…

From the dialogue above, Alexander has been collectiong corpses inside his jar.

In addition, if Alexander takes the corpses of strong hero, he will also get stronger.

Fighting with Us

Finally, Alexander challenges us to become a great champion.

Alexander
I doubt there’s a single soul who could’ve handled that giant, other than you. It was practically a god…
Of course I count myself, the great Alexander, among the many.
Which means, I’ve but one thing to ask of you. Would you kindly undertake my ordeal?
Come and tell me when you’re ready. I’ve been longing to fight a warrior as accomplished as you.

Alexander
You are ready then, I take it? Then let us begin! I am the great jar warrior, Iron Fist Alexander! Lend me strength, O warriors within! Let us become one champion, together!

It is respectable that Alexander challenges us, a strongest Tarnished, to a life-threatening battle to approach a heigher level.

True Identity

And just before Alexander is dying, he drops the items Shard of Alexander and Alexander’s Innards.

Shard of Alexander
Shard of the late Alexander, a shattered warrior jar.
Greatly boosts the attack power of skills.
Scraps of stewed flesh cling to the shard, and tatters of ornaments can be seen mingled within the slime. Relics of a red-haired champion, it would seem.

Alexander’s Innards
A keepsake of the warrior jar Alexander. Found at the core of the dead flesh that once filled the great jar.
The jars contain dregs inherited from those who came before. Thus are warriors passed from jar to jar, carrying dreams of greatness.

Let’s think about the identity of Alexander and the jar clan.

To conclude, it is speculated that Radagon created the jar clan, including Alexander.

First, as to who the “red-haired champion” in the text of Shard of Alexander is, the candidates are a giant, Radagon, Radahn, Ranni, and Rykard.

Then, the word “Relics” implies the red-haired champion has already died.

So, Radahn and Rykard are not the red-haired champion because they are alive when we first met the Alexander.

In addition, Ranni is not called any champion, so she must not the red-haired champion.

So, the red-haired champion would be a giant or Radagon.

However, considering what Miriel said, the red-haired champion would be Radagon

Miriel
You wish to know more of Lord Radagon? Lord Radagon was a great champion, possessed of flowing red locks.

And, the text, “Thus are warriors passed from jar to jar, carrying dreams of greatness.”, suggests that jar warriors have the destiny to fight forever.

This foreverness is the central concept of the Golden Order that Radagon worships.

From these points, we can see the jars are relics of Radagon and they are fighting forever.

So, it is speculated that the jar clan, including Alexander, was created by Radagon using the Golden Order.

Postscript

This article explained the lore of Alexander.