Both tanks can be played very aggressively as assassins or better (joke). They both have skills that seperates thrm from other tanks.
Grock
Grock has enhanced physical and magic resistance and CC immunity whenever he charges up that Skill 1 near a wall. Skill 1 can also deal ridiculously high amounts of damage, which I find very useful when farming or clearing minion waves. His Skill 2 may work both ways, but has great utility if used masterfully. His Ult is as explosive AF, and knocks up enemies. It also deals extra damage and further lowers its CDR when he makes contact with a wall.
Now what kind of spell he need?
Usually execute is the best choice, because grock can deal a lot of damage but happen sometimes that enemy can escape with 1 hp so execute help for this last hit and also arrival is a good spell.
How he need to rotate so?
I think to protect the mid laner from beginning then in late game my priority is the marksman.
When the match start I go in the mid lane to stay in the bash charging the first skill and waiting for enemy (sometimes in a few second we have the first blood).
For me is important to rotate always with mid-laner following him and helping with farm.
Also is important when you use Grock to move near to the walls like I said because of anti CC.
Which heroes can be a problem for grock?
A problem can be chou, waiting the end for my first skill.
Also marksman in late game, like karrie and claude, or franco because is the only hero with this specific ability with CC.
Khufra
Khufra is a CC machine. His damage dealing capabilities scales with his HP, which means he remains deadly throughout the game. His Skill 1 has the farthest blink that can pass through the thickest of obstacles (yup, it passes through turrets) and knocks up enemy heroes it comes into contact with. It can also disrupt the enemies’ Ult, including Mino’s dreaded Minoan Fury. Skill 2 boosts his physical and magic resistance by 100% throughout the duration of the skill, raises his movement speed, and deals both physical and magic damage upon casting and whenever he comes into contact with the ground. If I’m not mistaken, his Skill 2 will jump over certain obstacles in the next patch update, which is a big buff. His Skill 3 pushes the enemies in its proximity towards the direction where you slide it, and if it hits obstacles like turrets, turret stumps, or walls, it stuns them and deals extra damage.
If you are to ask me who I’d pick, I’d be leaning towards Khufra because he is a lot easier to use, his skill set can be used as offensive or defensive tools, can bring the element of surprise against unsuspecting enemies even from afar (take note that his hitbox using his Skill 1 goes slightly beyond the skill pointer, which is a bit further than full screen, similar to Gatot’s Ult).
And is a hard counter against hard-to-deal-with heroes such as Mino, Fanny, Helcurt, Esmeralda, Chou, Guinevere, Leomord, Harith, Claude, Kimmy, and anyone who relies on blink skills. His passive is a ranged basic attack that slows the opponent down and restores 8% of his max HP, with a 12-second cooldown that can be lowered by 4 seconds further by CCing the opponent, which I find very useful against fleeing low-HP opponents.
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