#!/usr/bin/perl -w
use strict;
use Data::Dump qw(pp);

my @players = ( {name => 'Bob', deaths => 2, kills => 5},
                {name => 'Bennie', deaths => 1, kills =>13},
                {name => 'Bob', deaths => 10, kills => 10},
                {name => 'Jane', deaths => 0, kills =>30}
               );
my %playerHoH;

foreach my $href (@players)
{
   my $name = $href->{name};
   $playerHoH{$name}{deaths} += $href->{deaths};
   $playerHoH{$name}{kills}  += $href->{kills};
}

# adding new player is easy... same case as adding deaths and
# kills to an existing player.
# $palyerHoH{name} will be created if it doesn't already exist.

$playerHoH{mary}{deaths} += 4;
$playerHoH{mary}{kills}  += 20;

print '%playerHOH = ',pp(\%playerHoH),"\n";

__END__
Prints:
\%playerHOH = {
  Bennie => { deaths => 1, kills => 13 },
  Bob    => { deaths => 12, kills => 15 },
  Jane   => { deaths => 0, kills => 30 },
  mary   => { deaths => 4, kills => 20 },
}