In Cyrillic tradional typography the shape of U+416 (capital zhe), U+436 
(small zhe) is strongly related with U+436 (capital ka), U+43a (small ka): zhe 
consists of two ka letters. The capital and small letters are similar. Left 
tail of "ya" (U+42f, U+44f) letter is sometimes correlated with "ka". At now 
DejaVu fonts have mess with the shapes of this letters. There may be several 
shapes:

1. Strait lines like Latin "k" of Serif font without ascender.

2. Curly lines. Look for example at MS Arial font.

3. Sometimes modern fonts have glyphs similar Latin "K" or Cyrillic "zhe" of 
Serif font. 

The first and second items can be mixed (one tail being strait, another being 
curly). The third varint is untraditional due to bad readability of 
Cyrillic "zhe" letters. The future shape of the letters should be dicussed. I 
prefer the first variant.