These are scarce. Be careful not to level up every character you unlock; focus on your main teams.
Use your strongest team (like Spider Society) to climb ranks for daily Power Cores.
Use Power Cores to refresh campaign energy 4 times a day. This increases XP, levels you up faster, and provides more farming opportunities. msf.ace
If you share your goal, I can give you a more specific team-building roadmap. BEGINNER's GUIDE 2025 - MARVEL Strike Force - MSF
Focus on specialized raid teams like Hive Mind/Rebirth (Bio), X-treme/Deathseed (Mutant), and Bifrost (Mystic). These are scarce
Progress through Heroes/Villains/Nexus to unlock required characters and gear.
Almost all early-game character offers are poor value; invest in energy refreshes instead. Use Power Cores to refresh campaign energy 4 times a day
Focus on unlocking and building the Spider Society team early; they are highly effective in early Arena and Raid modes.