translation - What does キワモノ mean?

I'm slowly trying to read through a light novel and came across this sentence:

襲撃を予定してみたものの、集まったメンツは見事にキワモノばかりの盗賊団だ。

What does that キワモノ (kiwamono) mean? None of the dictionaries I've tried seem to know the meaning of that word.

Answer

キワ in キワモノ comes from 際どい:

際どい

1. very close; close; narrow (e.g. narrow victory); dangerous; risky; hazardous​


2. suggestive; bordering on the obscene; risqué; delicate (e.g. question); immoral; questionable; shady​

In this case キワモノ refers to someone who is very questionable, abnormal, peculiar or even insane for a thief. For example, a thief weighting 400 lbs, a thief who faints at the sight of blood, a thief who uses a guitar instead of a knife... These can be called キワモノ.

According to dictionaries 際物 in kanji means seasonal/temporary/trendy/non-universal articles and topics, but I think this meaning is obsolete. キワモノ as a slang word is usually written in katakana.