ヤー公 is read as やーこう (yaakou) and means yakuza.
やーこう
yaakou
しゅじんこう
head (of a household)
おおやけ
public (use, matter, forum, etc.)
きみ
he
たいこう
archduke
ほうこう
live-in domestic service
くまこうはちこう
the average Joe
くげ
Imperial Court
こうかい
opening to the public
こうめい
Komeito (Japanese political party)
こうりつ
public (institution)
こうせい
justice
こうげん
declaration