In Quick Combat, 5/6 unupgraded psychic elementals with a hero having 0-0-3-3 stats, without spells, and without combat skills, can take out a Hive of 18 x 5 = 90 Vipers (12 Vivs) with a loss of 4/3 elementals;

Under the same conditions (hero with zero stats):

2 elementals take out a Hive of 06 x 5 = 30 Vipers (4 Vivs) with a loss of 1 elemental;
3 elementals take out a Hive of 09 x 5 = 45 Vipers (6 Vivs) with a loss of 1-2 elementals;
3 elementals take out a Hive of 12 x 5 = 60 Vipers (8 Vivs) with a loss of 2 elementals.

Obviously, a hero with the Defense skill or a non-zero defense stat may lose even fewer elementals.