Breathing New Life [Part 5]

Question

This is the final part of a 5 part series.

Links to the first 4:

Part 1: Large and in charge [solved]

Part 2: Small and resilient [solved]

Part 3: Immovable object [solved]

Part 4: Unstoppable force [solved]

(parts 1-4 can be solved out of order)

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Now for Part 5:

Part 1---

A good problem solver peers into the past,
once you find me, it's quiet at last.

Completing this riddle is the ultimate test,
for after its done, you will need your rest.

Part 2---

The other day I screamed "JSTYX" out loud all confused,
To figure out what it means, I'd be greatly amused.

As a great riddler, I've not spoken this word,
for if I had, that'd just be absurd.

After some twisting and thrashing, I'll have solved this problem,
the four other parts, I'm sure that I've solved them.

The problems the key, I know it, I know it,
But instead of sharing I might as well throw it.

As with the past, a similar method involved,
This time it's much harder, and has greatly evolved.

Conclusion---

With all of these pieces, you look back in time,
This is the end of the puzzle, but not my last rhyme.

What/who am I?

Answer 1

The answer is

Tombstone

Because..

A good problem solver peers into the past,
once you find me, it's quiet at last.

Tulip
Ocarina
Mountain
Button I used the first letters of each of the previous puzzle's solutions to find the word Tomb

Then...

Completing this riddle is the ultimate test,
for after its done, you will need your rest.

Your final resting place is generally in a tomb

The other day I screamed "JSTYX" out loud all confused,
To figure out what it means, I'd be greatly amused.

Subtract 5 from each of the letters of "JSTYX" to get "ENOTS"

The problems the key, I know it, I know it,
But instead of sharing I might as well throw it.

As with the past, a similar method involved,
This time it's much harder, and has greatly evolved.

This is STONE backwards
A stone is often thrown, rather than shared.
Again, we're looking into the past, but this time it's to reverse the word. A stone is hard and is weathered from larger stones, over time.

The only thing I can think of, on the titles, is that they're backwards:

Large and in charge

The word tulip comes from the Persian word, delband, which means Turban - generally worn by a Persian ruler.

Small and resilient

An ocarina is a small, handheld, instrument - often made of metal.

Immovable object

A mountain....well it's not going anywhere anytime soon

Unstoppable Force

The goal of a button is to hold something in place - to keep it from moving

Breathing New Life

This one breaks the pattern, but tombs do feed carrion and other bugs that inhabit graveyards.