An ever-changing riddle

Question

To find me, you must first find my pairs,
A swarm of creatures, skittering inside walls,
Torturing the old way, sometimes using a chair,
A powerful figure, there until its empire falls,
Or some activities, one might enjoy in their lair.

Who am I?

Hint:

A connection between all these words is what you seek
Once found, you won't be able to fall to the riddle's trick

Hint 2:

It seems the riddle is getting a lot of people stuck
Only four letters are needed, and maybe a sliver of luck

Hint 3:

My pairs have the same letters as I do,
Just rearrange them, to find something new!

Answer 1

I think you are:

STAR - the trick here is that all four of the other lines clue four-letter words (Hint 2) that are anagrams of these same four letters (Hint 3). Moreover, this word and the four others concealed in the puzzle are the only five common words that can be formed from these letters (Hint 1).

A swarm of creatures, skittering inside walls,

RATS are creatures found in walls.

Torturing the old way, sometimes using a chair,

TARS - tarring and feathering was a form of torture and punishment used in the past.

A powerful figure, there until its empire falls,

TSAR - the equivalent of an Emperor in the former Bulgarian, Serbian and Russian empires.

Or some activities, one might enjoy in their lair.

ARTS (like drawing, painting, and other creative pastimes) might be enjoyed in your spare time (and spare room).

This leaves just...

...STAR as the only other common anagram of these four letters. We have found your 'pairs' (i.e. other words sharing the same letters) through their 'ever-changing' ordering, so now we have found you too!

Answer 2

This is not my forté, but how about

term

pairs of words are terms. termites skitter inside walls, eating wood.

powerful figure - might (from -mite)?

also a fixed time which may dominate our lives until it 'falls'.

also the end of a pregnancy that one of the mites (the queen) may enjoy?

connection between words is a term...