How come 将 is a "future marker" and a "passive marker"? Any good logical theories on the subject? What twisted life must have 将 took to merge such functions into one glyph? 

For my background 将 as 把(to take) and 将 as 且(further) are queit different in their meaning.

All linguistic articles on the subject are quite hard for me to read (all of them in chinese, of course). And usual books just give you rules but not how those rule originated in the first place.

P.S. Please don't tell me anything about 把, 且 or any other modern 将 equivalent. I'm interested in the evolution, the etymology of the functions of 将 and how they come to be so "perpendicular".

I know that 将 is like 把, it's almost similar, it's used in books more not in everyday talk and so on... 

I care only about evolution, etymology. Thanks.
将 before a verb is functioning as a [modal verb]: 'will / will soon'

Example:
(将)回家 = (will) go home
(将)死 = (will) die/ will die (soon)

将/把 before a noun is functioning as a [depositive marker] that marks the noun to be deposited by the verb

Example:
打死他 (beat him to death)
将他打死 (take him, and beat to death) - 将 marks 他 as the object that's being deposited by the verb 打死

将 https://en.wiktionary.org/wiki/%E5%B0%87
Phono-semantic compound (形聲, OC *ʔsaŋ, *ʔsaŋs): phonetic 爿 (OC *braːn, *zaŋ, “bed; small table”) + semantic ⺼ (“meat”) + semantic 寸 (“hand”) – &gt;to offer meat as tribute by putting it on the table.

&quot;to offer meat&quot; is to &quot;deposit the meat' that's how 将 acquired the function of [depositive marker] that marks object to be deposited of
Just read the article at WiKi
Stumpy Joe Pete wrote:

how did the &quot;to want, to wish, to approach&quot; meaning come to be attached to that character? Did it come about later, or have both meanings been attached to the same character/pronunciation as far back as we can go?

from Sino-Tibetan root:
⺼ (“meat”) +  寸 (“hand”) is the semantic component of 將 . It describes the action of handling a piece of meat; 爿 (table) is a semantic + phonetic component of 將.
The original meaning of the character 將 meant &quot;to offer meat as a tribute to gods by putting it on the table&quot;
The action of 將 described (put meat on the table) acquired the function of [depositive marker] later
From Austroasiatic root:
&quot;Khmer ចង់ &quot;  (to want, to wish, to approach) was imported to Chinese language in ancient time, and the existing character 將 was loaned to express this word for phonetic  reason. Since  &quot;to want, to wish&quot; is related to future event. meaning of the modal verb &quot;will&quot; was added to 將 later