床の上でキャラクターを切り替える

using UnityEngine;

public class SimpleMover : MonoBehaviour
{
    [SerializeField] private float speed = 6f;
    [SerializeField] private float turnSpeed = 12f;

    void Update()
    {
        // -1 .. 1 from A/D and W/S
        float h = Input.GetAxisRaw("Horizontal");
        float v = Input.GetAxisRaw("Vertical");

        Vector3 dir = new Vector3(h, 0f, v);
        if (dir.sqrMagnitude < 0.01f) return;      // no input, nothing to do

        dir.Normalize();                            // diagonal is not faster
        transform.position += dir * speed * Time.deltaTime;

        // face the direction of travel
        Quaternion target = Quaternion.LookRotation(dir);
        transform.rotation = Quaternion.Slerp(transform.rotation, target, turnSpeed * Time.deltaTime);
    }
}

using System.Collections.Generic;
using UnityEngine;

public class CharacterSwitcher : MonoBehaviour
{
    [SerializeField] private List<SimpleMover> characters = new List<SimpleMover>();
    [SerializeField] private Transform highlightRing;   // optional marker

    private int activeIndex = 0;

    void Start()
    {
        Select(0);
    }

    void Update()
    {
        // number keys 1..9
        for (int i = 0; i < characters.Count && i < 9; i++)
            if (Input.GetKeyDown(KeyCode.Alpha1 + i))
                Select(i);

        // Tab cycles to the next one
        if (Input.GetKeyDown(KeyCode.Tab))
            Select((activeIndex + 1) % characters.Count);
    }

    public void Select(int index)
    {
        if (index < 0 || index >= characters.Count) return;

        activeIndex = index;

        for (int i = 0; i < characters.Count; i++)
            characters[i].enabled = (i == index);      // only one may move

        if (highlightRing != null)
            highlightRing.SetParent(characters[index].transform, false);

        Debug.Log("Now controlling: " + characters[index].name);
    }

    public Transform ActiveCharacter => characters[activeIndex].transform;
}

using UnityEngine;

public class SwapCamera : MonoBehaviour
{
    [SerializeField] private CharacterSwitcher switcher;
    [SerializeField] private Vector3 offset = new Vector3(0f, 12f, -14f);
    [SerializeField] private float smooth = 4f;

    void LateUpdate()                      // after everyone has moved
    {
        Transform target = switcher.ActiveCharacter;
        Vector3 wanted = target.position + offset;

        transform.position = Vector3.Lerp(transform.position, wanted, smooth * Time.deltaTime);
        transform.LookAt(target.position + Vector3.up);
    }
}